0001564590-19-028042 | 10-Q | XBRL Viewer | Intellia Therapeutics INC

Equity-Based Compensation - Schedule of Equity-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 4,404	$ 4,901	$ 8,996	$ 9,008
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	2,096	2,633	3,879	5,026
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 2,308	$ 2,268	$ 5,117	$ 3,982

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 49,140	$ 58,856
Marketable securities - current	221,959	255,203
Accounts receivable	4,188	7,547
Proceeds due from at-the-market offerings	27,140
Prepaid expenses and other current assets	4,710	3,371
Total current assets	307,137	324,977
Marketable securities - noncurrent	4,739
Property and equipment, net	16,694	17,061
Operating lease right-of-use assets	20,923
Other assets	2,948	5,277
Total Assets	352,441	347,315
Current Liabilities:
Accounts payable	1,848	2,708
Accrued expenses	11,898	10,742
Current portion of lease liability	5,065
Current portion of deferred revenue	19,652	27,122
Total current liabilities	38,463	40,572
Deferred revenue, net of current portion	22,508	28,810
Long-term lease liability	14,604
Other long-term liabilities		13
Commitments and contingencies
Stockholders’ Equity:
Common stock, $0.0001 par value; 120,000,000 shares authorized; 47,714,575 and 45,224,480 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	5	5
Additional paid-in capital	525,574	478,968
Accumulated other comprehensive income (loss)	255	(28)
Accumulated deficit	(248,968)	(201,025)
Total stockholders’ equity	276,866	277,920
Total Liabilities and Stockholders’ Equity	$ 352,441	$ 347,315

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended		62 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (47,623)	$ (43,575)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,621	2,085
Loss (gain) on disposal of property and equipment	17	(29)
Equity-based compensation	8,996	9,008
Accretion of investment discounts	(2,630)
Non-cash lease expense	462
Changes in operating assets and liabilities:
Accounts receivable	3,359	1,862
Prepaid expenses and other current assets	(1,339)	199
Accounts payable	(293)	(1,599)
Accrued expenses	947	305
Deferred revenue	(13,772)	(9,009)
Other assets	125	564
Other long-term liabilities		(76)
Net cash used in operating activities	(49,130)	(40,265)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(2,474)	(2,750)
Purchases of marketable securities	(182,582)
Maturities of marketable securities	214,000
Net cash provided by (used in) investing activities	28,944	(2,750)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from common stock offerings, net of offering costs	7,912		$ 580,200
Proceeds from options exercised	2,024	7,277
Issuance of shares through employee stock purchase plan	534	598
Net cash provided by financing activities	10,470	7,875
Net decrease in cash and cash equivalents	(9,716)	(35,140)
Cash and cash equivalents, beginning of period	58,856	340,678
Cash and cash equivalents, end of period	49,140	305,538	$ 49,140
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Purchases of property and equipment unpaid at period end	867	$ 1,417
Proceeds from at-the-market offerings unpaid at period end	27,140
Right-of-use assets acquired under operating leases	$ 1,343

Fair Value Measurements

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurements

3.	Fair Value Measurements

The Company classifies fair value-based measurements using a three-level hierarchy that prioritizes the inputs used to measure fair value. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: Level 1, quoted market prices in active markets for identical assets or liabilities; Level 2, observable inputs other than quoted market prices included in Level 1, such as quoted market prices for markets that are not active or other inputs that are observable or can be corroborated by observable market data; and Level 3, unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities, including certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs.

The Company’s financial instruments as of June 30, 2019 and December 31, 2018 included cash and cash equivalents, marketable securities, accounts receivable and accounts payable. As of June 30, 2019 and December 31, 2018, the Company’s financial assets recognized at fair value on a recurring basis consisted of the following:

	Fair Value as of June 30, 2019
	Total		Level 1		Level 2		Level 3
	(In thousands)
Cash equivalents	$	45,799	$	45,799	$	-	$	-
Marketable securities:
U.S. Treasury securities		146,713		146,713		-		-
Financial institution debt securities		53,110		-		53,110		-
Corporate debt securities		18,892		-		18,892		-
Other asset-backed securities		7,983		-		7,983		-
Total marketable securities		226,698		146,713		79,985		-
Total	$	272,497	$	192,512	$	79,985	$	-

	Fair Value as of December 31, 2018
	Total		Level 1		Level 2		Level 3
	(In thousands)
Cash equivalents	$	45,986	$	45,986	$	-	$	-
Marketable securities:
U.S. Treasury securities		165,948		165,948		-		-
Financial institution debt securities		65,420		-		65,420		-
Corporate debt securities		23,835		-		23,835		-
Total marketable securities		255,203		165,948		89,255		-
Total	$	301,189	$	211,934	$	89,255	$	-

The Company’s financial assets, which include cash equivalents and marketable securities, have been initially valued at the transaction price, and subsequently revalued at the end of each reporting period, utilizing third-party pricing services or other observable market data. The pricing services utilize industry standard valuation models and observable market inputs to determine value. After completing our validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of June 30, 2019 or December 31, 2018.

Other financial instruments, including accounts receivable and accounts payable, are carried at cost, which approximate fair value due to the short duration and term to maturity.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Related Party Transactions - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	May 31, 2016	Jul. 31, 2014	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
General and administrative expenses			$ 13,118,000	$ 7,805,000	$ 23,651,000	$ 15,211,000
Collaboration revenue			11,118,000	7,677,000	21,551,000	15,146,000
Deferred revenue			$ 42,160,000	$ 50,859,000	$ 42,160,000	$ 50,859,000	$ 55,932,000	$ 59,868,000
Caribou [Member]
Related Party Transaction [Line Items]
Percentage of related party obligation		30.00%	30.00%	30.00%	30.00%	30.00%
General and administrative expenses			$ 700,000	$ 300,000	$ 900,000	$ 500,000
Caribou [Member] \| Minimum [Member]
Related Party Transaction [Line Items]
Percentage of shares owned			5.00%		5.00%
Novartis [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Issuance of common stock through at-the-market offering, net of issuance costs, shares	277,777
Collaboration revenue			$ 4,800,000	$ 2,400,000	$ 9,500,000	$ 4,700,000
Accounts receivable			1,000,000.0		1,000,000.0		6,000,000.0
Deferred revenue			$ 7,000,000.0		$ 7,000,000.0		$ 14,500,000
Novartis [Member] \| Minimum [Member] \| Collaborative Arrangement [Member]
Related Party Transaction [Line Items]
Percentage of shares owned			10.00%		10.00%

Stockholders’ Equity (Tables)

6 Months Ended

Jun. 30, 2019

Equity [Abstract]

Schedule of Changes in Stockholders’ Equity

The following tables present changes in stockholders’ equity for the six-month periods ended June 30, 2019 and 2018 (in thousands, except share data):

						Additional		Accumulated Other						Total
	Common					Paid-In		Comprehensive			Accumulated			Stockholders’
	Shares			Amount		Capital		Income (Loss)			Deficit			Equity (Deficit)
Balance at December 31, 2018		45,224,480		$	5	$	478,968	$	(28	)	$	(201,025	)	$	277,920
Retroactive adjustment to beginning accumulated deficit for adoption of ASC 842		-			-		-		-			(320	)		(320	)
Issuance of common stock through at-the-market offerings, net of issuance costs of $120		223,818			-		3,639		-			-			3,639
Exercise of stock options		30,800			-		360		-			-			360
Equity-based compensation		-			-		4,592		-			-			4,592
Other comprehensive gain		-			-		-		87			-			87
Net loss		-			-		-		-			(21,940	)		(21,940	)
Balance at March 31, 2019		45,479,098		$	5	$	487,559	$	59		$	(223,285	)	$	264,338
Issuance of common stock through at-the-market offerings, net of issuance costs of $3		1,986,579			-		31,413		-			-			31,413
Exercise of stock options		203,072			-		1,664		-			-			1,664
Issuance of shares under employee stock purchase plan		45,826			-		534		-			-			534
Equity-based compensation		-			-		4,404		-			-			4,404
Other comprehensive gain		-			-		-		196			-			196
Net loss		-			-		-		-			(25,683	)		(25,683	)
Balance at June 30, 2019		47,714,575		$	5	$	525,574	$	255		$	(248,968	)	$	276,866

						Additional		Accumulated Other						Total
	Common					Paid-In		Comprehensive			Accumulated			Stockholders’
	Shares			Amount		Capital		Income (Loss)			Deficit			Equity (Deficit)
Balance at December 31, 2017		42,384,623		$	4	$	421,706	$	-		$	(121,113	)	$	300,597
Retroactive adjustment to beginning accumulated deficit for adoption of ASU 2014-09		-			-		-		-			5,431			5,431
Exercise of stock options		709,321			-		6,720		-			-			6,720
Cancellation of restricted stock		(2,022	)		-		-		-			-			-
Equity-based compensation		-			-		4,107		-			-			4,107
Net loss		-			-		-		-			(21,356	)		(21,356	)
Balance at March 31, 2018		43,091,922		$	4	$	432,533	$	-		$	(137,038	)	$	295,499
Exercise of stock options		68,163			-		557		-			-			557
Issuance of shares under employee stock purchase plan		32,707			-		598		-			-			598
Cancellation of restricted stock		(4,780	)		-		-		-			-			-
Equity-based compensation		-			-		4,901		-			-			4,901
Net loss		-			-		-		-			(22,219	)		(22,219	)
Balance at June 30, 2018		43,188,012		$	4	$	438,589	$	-		$	(159,257	)	$	279,336

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Summary of Financial Assets Recognized at Fair Value on Recurring Basis

As of June 30, 2019 and December 31, 2018, the Company’s financial assets recognized at fair value on a recurring basis consisted of the following:

	Fair Value as of June 30, 2019
	Total		Level 1		Level 2		Level 3
	(In thousands)
Cash equivalents	$	45,799	$	45,799	$	-	$	-
Marketable securities:
U.S. Treasury securities		146,713		146,713		-		-
Financial institution debt securities		53,110		-		53,110		-
Corporate debt securities		18,892		-		18,892		-
Other asset-backed securities		7,983		-		7,983		-
Total marketable securities		226,698		146,713		79,985		-
Total	$	272,497	$	192,512	$	79,985	$	-

	Fair Value as of December 31, 2018
	Total		Level 1		Level 2		Level 3
	(In thousands)
Cash equivalents	$	45,986	$	45,986	$	-	$	-
Marketable securities:
U.S. Treasury securities		165,948		165,948		-		-
Financial institution debt securities		65,420		-		65,420		-
Corporate debt securities		23,835		-		23,835		-
Total marketable securities		255,203		165,948		89,255		-
Total	$	301,189	$	211,934	$	89,255	$	-

Equity-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Equity-Based Compensation Expense

Equity-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(In thousands)
Research and development	$	2,096	$	2,633	$	3,879	$	5,026
General and administrative		2,308		2,268		5,117		3,982
Total	$	4,404	$	4,901	$	8,996	$	9,008

Summary of Restricted Stock Activity

The following table summarizes the Company’s restricted stock activity for the six months ended June 30, 2019:

	Number of Shares			Weighted Average Grant Date Fair Value per Share
Unvested restricted stock as of December 31, 2018		109,073		$	15.53
Granted		-			-
Vested		(36,462	)		1.34
Cancelled		-			-
Unvested restricted stock as of June 30, 2019		72,611		$	22.66

Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted

Key assumptions used to apply this pricing model were as follows:

	Three Months Ended June 30,		Six Months Ended June 30,
	2019	2018	2019	2018
Risk-free interest rate	2.1%	2.8%	2.4%	2.6%
Expected life of options	5.5-6.0 years	5.5-6.25 years	5.5-6.0 years	5.5-6.25 years
Expected volatility of underlying stock	67.9%	87.7%	68.6%	89.0%
Expected dividend yield	0.0%	0.0%	0.0%	0.0%

Summary of Stock Option Activity

The following is a summary of stock option activity for the six months ended June 30, 2019:

	Number of Options			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(In years)		(In thousands)
Outstanding at December 31, 2018		5,037,663		$	15.63
Granted		793,813			14.54
Exercised		(233,872	)		8.65
Forfeited		(282,108	)		18.79
Outstanding at June 30, 2019		5,315,496		$	15.61		8.14	$	14,978
Exercisable at June 30, 2019		2,165,526		$	13.43		7.01	$	10,193

Stockholders’ Equity

6 Months Ended

Jun. 30, 2019

Equity [Abstract]

Stockholders’ Equity

9.	Stockholders’ Equity

The following tables present changes in stockholders’ equity for the six-month periods ended June 30, 2019 and 2018 (in thousands, except share data):

						Additional		Accumulated Other						Total
	Common					Paid-In		Comprehensive			Accumulated			Stockholders’
	Shares			Amount		Capital		Income (Loss)			Deficit			Equity (Deficit)
Balance at December 31, 2018		45,224,480		$	5	$	478,968	$	(28	)	$	(201,025	)	$	277,920
Retroactive adjustment to beginning accumulated deficit for adoption of ASC 842		-			-		-		-			(320	)		(320	)
Issuance of common stock through at-the-market offerings, net of issuance costs of $120		223,818			-		3,639		-			-			3,639
Exercise of stock options		30,800			-		360		-			-			360
Equity-based compensation		-			-		4,592		-			-			4,592
Other comprehensive gain		-			-		-		87			-			87
Net loss		-			-		-		-			(21,940	)		(21,940	)
Balance at March 31, 2019		45,479,098		$	5	$	487,559	$	59		$	(223,285	)	$	264,338
Issuance of common stock through at-the-market offerings, net of issuance costs of $3		1,986,579			-		31,413		-			-			31,413
Exercise of stock options		203,072			-		1,664		-			-			1,664
Issuance of shares under employee stock purchase plan		45,826			-		534		-			-			534
Equity-based compensation		-			-		4,404		-			-			4,404
Other comprehensive gain		-			-		-		196			-			196
Net loss		-			-		-		-			(25,683	)		(25,683	)
Balance at June 30, 2019		47,714,575		$	5	$	525,574	$	255		$	(248,968	)	$	276,866

						Additional		Accumulated Other						Total
	Common					Paid-In		Comprehensive			Accumulated			Stockholders’
	Shares			Amount		Capital		Income (Loss)			Deficit			Equity (Deficit)
Balance at December 31, 2017		42,384,623		$	4	$	421,706	$	-		$	(121,113	)	$	300,597
Retroactive adjustment to beginning accumulated deficit for adoption of ASU 2014-09		-			-		-		-			5,431			5,431
Exercise of stock options		709,321			-		6,720		-			-			6,720
Cancellation of restricted stock		(2,022	)		-		-		-			-			-
Equity-based compensation		-			-		4,107		-			-			4,107
Net loss		-			-		-		-			(21,356	)		(21,356	)
Balance at March 31, 2018		43,091,922		$	4	$	432,533	$	-		$	(137,038	)	$	295,499
Exercise of stock options		68,163			-		557		-			-			557
Issuance of shares under employee stock purchase plan		32,707			-		598		-			-			598
Cancellation of restricted stock		(4,780	)		-		-		-			-			-
Equity-based compensation		-			-		4,901		-			-			4,901
Net loss		-			-		-		-			(22,219	)		(22,219	)
Balance at June 30, 2018		43,188,012		$	4	$	438,589	$	-		$	(159,257	)	$	279,336

Equity-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding, Beginning Balance	5,037,663
Number of options, Granted	793,813
Number of options, Exercised	(233,872)
Number of options, Forfeited	(282,108)
Number of Options, Outstanding, Ending Balance	5,315,496
Number of Options, Exercisable	2,165,526
Weighted Average Exercise Price per Share, Outstanding, Beginning Balance	$ 15.63
Weighted Average Exercise Price per Share, Granted	14.54
Weighted Average Exercise Price per Share, Exercised	8.65
Weighted Average Exercise Price per Share, Forfeited	18.79
Weighted Average Exercise Price per Share, Outstanding, Ending Balance	15.61
Weighted Average Exercise Price per Share, Exercisable	$ 13.43
Weighted Average Remaining Contractual Term, Outstanding	8 years 1 month 20 days
Weighted Average Remaining Contractual Term, Exercisable	7 years 3 days
Aggregate Intrinsic Value, Outstanding	$ 14,978
Aggregate Intrinsic Value, Exercisable	$ 10,193

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Jul. 26, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	NTLA
Entity Registrant Name	INTELLIA THERAPEUTICS, INC.
Entity Central Index Key	0001652130
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		48,543,069
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-37766
Entity Tax Identification Number	364785571
Entity Address, Address Line One	40 Erie Street
Entity Address, Address Line Two	Suite 130
Entity Address, City or Town	Cambridge
Entity Address, State or Province	Massachusetts
Entity Address, Postal Zip Code	02139
City Area Code	857
Local Phone Number	285-6200

Collaborations - Additional Information (Detail)	1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended	39 Months Ended	54 Months Ended
Collaborations - Additional Information (Detail)	Jul. 31, 2018 USD ($) shares	Apr. 30, 2016 USD ($)	Jan. 31, 2015 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) PerformanceObligation	Jun. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue				$ 11,118,000	$ 7,677,000	$ 21,551,000	$ 15,146,000
Deferred revenue				42,160,000	50,859,000	42,160,000	50,859,000		$ 42,160,000	$ 42,160,000	$ 55,932,000	$ 59,868,000
Novartis [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Additional payments received on each target						1,000,000.0
Estimated fair value of units			$ 11,600,000
Difference between cash proceeds received and estimated fair value of preferred units			2,600,000
Novartis [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development based milestone payments under agreement			30,300,000
Regulatory based milestone payments for first indication			50,000,000.0
Regulatory based milestone payments for second indication			50,000,000.0
Sales based milestone payments under agreement			100,000,000.0
Novartis [Member] \| 2014 Novartis Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions			10,000,000.0			10,000,000.0
Technology access fees			20,000,000.0	20,000,000.0		20,000,000.0			20,000,000.0	20,000,000.0
Quarterly research payments			$ 1,000,000.0	20,000,000.0		20,000,000.0			20,000,000.0	20,000,000.0
Research Payments				17,000,000.0		17,000,000.0			17,000,000.0	17,000,000.0
Research term			5 years
Proceeds from issuance of preferred stock						$ 9,000,000.0
One time collaboration payment											10,000,000.0
Termination period of agreement						90 days
Number of performance obligations \| PerformanceObligation						2
Transaction price						$ 59,000,000.0
Transaction price allocated to preferred units purchased at fair value						11,600,000
Novartis [Member] \| 2014 Novartis Agreement [Member] \| HSC and CAR-T Cell Products [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Remaining transaction price allocated to combined performance obligation of licenses and associated research activities						$ 47,400,000
Combined performance obligation of licenses and associated research activities, revenue recognition period						5 years
Novartis [Member] \| 2014 Novartis Agreement [Member] \| LSCs [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of performance obligations \| PerformanceObligation						1
Transaction price						$ 10,000,000.0
Combined performance obligation of licenses and associated research activities, revenue recognition period						1 year
Novartis [Member] \| 2014 Novartis Agreement [Member] \| Scenario, Forecast [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Internalization fee								$ 50,000,000.0
Period allowed for editing limited number of platform targets								5 years
Novartis [Member] \| 2014 Novartis Agreement [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total research funding			$ 20,000,000.0
Novartis [Member] \| 2014 Novartis Agreement [Member] \| Maximum [Member] \| Scenario, Forecast [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Internalization fee milestone payment								$ 20,000,000.0
Milestone payment for additional post-internalization targets								$ 4,000,000.0
Novartis [Member] \| Unit Purchase Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceeds from issuance of preferred stock			$ 9,000,000.0
Novartis [Member] \| Novartis Arrangement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions										55,400,000
Collaboration revenue				4,800,000	2,400,000	$ 9,500,000	4,700,000			48,400,000
Aggregate transaction price remaining to be recognized				9,000,000.0		$ 9,000,000.0			9,000,000.0	9,000,000.0
Aggregate transaction price remaining to be recognized, period						through December 2019
Accounts receivable				1,000,000.0		$ 1,000,000.0			1,000,000.0	1,000,000.0	6,000,000.0
Deferred revenue				7,000,000.0		$ 7,000,000.0			7,000,000.0	7,000,000.0	14,500,000
Regeneron Pharmaceuticals Inc. [Member] \| Regeneron Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions		$ 75,000,000.0
One time collaboration payment		$ 25,000,000.0
Termination period of agreement		180 days
Number of performance obligations \| PerformanceObligation						3
Percentage of certain research and development costs to be funded		50.00%
Collaboration term extension period		2 years
Royalty payment obligation expiration period		12 years
Transaction price allocated to common stock						$ 50,000,000.0
Remaining transaction price allocated to combined performance obligation						75,000,000.0
Amount allocated to licenses to targets and associated research activities and evaluation plans						63,800,000
Amount allocated to technology collaboration and associated research activities						$ 11,200,000
Licenses to targets and associated research activities and evaluation plans performance period						6 years
Regeneron Pharmaceuticals Inc. [Member] \| Regeneron Agreement [Member] \| Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development based milestone payments under agreement		$ 25,000,000.0
Sales based milestone payments under agreement		185,000,000.0
Regulatory based milestone payments under agreement		110,000,000.0
Regeneron Pharmaceuticals Inc. [Member] \| Stock Purchase Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Purchase of common stock through private placement		$ 50,000,000.0
Regeneron Pharmaceuticals Inc. [Member] \| Co-Development and Co-Promotion Agreement Member [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Termination period of agreement	180 days
Compensation for prior work	$ 1,500,000
Payment of royalty percentage on net product sales	50.00%
Regeneron Pharmaceuticals Inc. [Member] \| Co-Development and Co-Promotion Agreement Member [Member] \| Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Options exercisable, number of shares exercisable \| shares	5
Collaborative arrangement obligation to be fund in development costs	$ 5,000,000.0
Regeneron Pharmaceuticals Inc. [Member] \| Regeneron Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue additions						$ 75,000,000.0			75,000,000.0
Transaction price						125,000,000.0
Collaboration revenue				6,300,000	5,300,000	12,000,000.0	10,400,000		57,700,000
Aggregate transaction price remaining to be recognized				35,200,000		$ 35,200,000			35,200,000	35,200,000
Aggregate transaction price remaining to be recognized, period						through April 2022
Deferred revenue				35,200,000		$ 35,200,000			35,200,000	35,200,000	41,400,000
Purchase of common stock through private placement						50,000,000.0
Payments due				3,200,000	$ 2,100,000	5,800,000	$ 4,100,000
Accounts receivable				$ 3,200,000		$ 3,200,000			3,200,000	$ 3,200,000	$ 1,500,000
Regeneron Pharmaceuticals Inc. [Member] \| Regeneron Arrangement \| Research and Development Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue									$ 17,900,000

Leases (Tables)

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Summary of Lease Costs and Other Information

The following table contains a summary of the lease costs recognized under Topic 842 and other information pertaining to the Company’s operating leases for the three and six months ended June 30, 2019:

	Three Months Ended			Six Months Ended
	June 30, 2019
	(in thousands)
Lease cost
Operating lease cost	$	1,880		$	3,583
Variable lease cost		460			997
Total lease cost	$	2,340		$	4,580
Other information
Operating cash flows used for operating leases	$	1,635		$	3,122
Operating lease liabilities arising from obtaining right-of-use assets		1,343			1,343
Weighted average remaining lease term	3.5 years			3.5 years
Weighted average discount rate		9.00	%		9.00	%

Schedule of Future Minimum Lease Payments

Future minimum lease payments under the Company’s non-cancelable operating leases as of June 30, 2019, are as follows:

Future Operating Lease Payments
Year Ending December 31,	(in thousands)
2019 (excluding the six months ended June 30, 2019)	$	3,355
2020		6,483
2021		6,618
2022		4,732
2023		871
Thereafter		943
Total lease payments	$	23,002
Less: imputed interest		(3,333	)
Less: leases not yet commenced		-
Total operating lease liabilities at June 30, 2019	$	19,669

Future minimum lease payments under the Company’s non-cancelable operating leases as of December 31, 2018, are as follows:

Year Ending December 31,	(In thousands)
2019	$	5,616
2020		4,963
2021		5,507
2022		3,861
Thereafter		-
	$	19,947

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	Summary of Significant Accounting Policies

The Company’s significant accounting policies are described in Note 2, “Summary of Significant Accounting Policies”, in our Annual Report. There have been no material changes during the six months ended June 30, 2019, other than the Company’s adoption of Accounting Standards Codification (“ASC”) 842 (as defined below) which is discussed in detail in this note.

Marketable Securities

The following table summarizes the Company’s available-for-sale marketable securities as of June 30, 2019 and December 31, 2018 at net book value:

	June 30, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury securities	$	146,552	$	161	$	-		$	146,713
Financial institution debt securities		53,041		69		-			53,110
Corporate debt securities		18,892		-		-			18,892
Other asset-backed securities		7,958		25		-			7,983
Total	$	226,443	$	255	$	-		$	226,698

	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury securities	$	165,959	$	2	$	(13	)	$	165,948
Financial institution debt securities		65,436		1		(17	)		65,420
Corporate debt securities		23,836		-		(1	)		23,835
Total	$	255,231	$	3	$	(31	)	$	255,203

The amortized cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At June 30, 2019 and December 31, 2018, the balance in the Company’s accumulated other comprehensive income (loss) was composed of activity related to the Company’s available-for-sale marketable securities. There were no realized gains or losses in the period ended June 30, 2019, and as a result, the Company did not reclassify any amounts out of accumulated other comprehensive income (loss) during the period. The Company did not have any securities in an unrealized loss position at June 30, 2019.

Leases

Effective January 1, 2019, the Company adopted ASC Topic 842, Leases (“ASC 842”), using the required modified retrospective approach and utilizing the effective date as its date of initial application. As a result, prior periods are presented in accordance with the previous guidance in ASC Topic 840, Leases.

At the inception of an arrangement, the Company determines whether an arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Most leases with a term greater than one year are recognized on the balance sheet as right-of-use assets and short-term and long-term lease liabilities, as applicable. The Company has elected not to recognize leases with terms of 12 months or less on the balance sheet. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew. The Company monitors its plans to renew its material leases on a quarterly basis.

Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the right-of-use asset may be required for items such as incentives received. The interest rate implicit in the Company’s leases is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate to discount lease payments, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. In its transition to ASC 842, the Company utilized the remaining lease term of its leases in determining the appropriate incremental borrowing rates.

In accordance with ASC 842, components of a lease should be allocated between lease components (e.g., land, building, etc.) and non-lease components (e.g., common area maintenance, consumables, etc.). The fixed and in-substance fixed contract consideration must be allocated based on the respective relative fair values to the lease components and non-lease components.

Although separation of lease and non-lease components is otherwise required, an expedient is available whereby the entity may account for each lease component and related non-lease component together as a single lease component. For new and amended leases beginning in 2019 and after, the Company has elected to account for the lease and non-lease components together as a single lease component for all underlying assets and allocate all of the contract consideration to the lease component only.

Revenue Recognition

The Company adopted Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606) and its related amendments (collectively known as “ASC 606”) on January 1, 2018 using the modified retrospective method.

At inception, the Company determines whether contracts are within the scope of ASC 606 or other topics. For contracts that are determined to be within the scope of ASC 606, revenue is recognized when a customer obtains control of promised goods or services. The amount of revenue recognized reflects the consideration to which the Company expects to be entitled to receive in exchange for these goods and services. To achieve this core principle, the Company applies the following five steps (i) identify the contract with the customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when or as the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when the Company determines that collection of substantially all consideration for goods and services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration.

Performance obligations promised in a contract are identified based on the goods and services that will be transferred to the customer that are both capable of being distinct and are distinct in the context of the contract. To the extent a contract includes multiple promised goods and services, the Company applies judgment to determine whether promised goods and services are both capable of being distinct and distinct in the context of the contract. If these criteria are not met, the promised goods and services are accounted for as a combined performance obligation.

The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods and services to the customer. To the extent the transaction price includes variable consideration, the Company estimates the amount of variable consideration that should be included in the transaction price utilizing either the expected value method or the most likely amount method, depending on the nature of the variable consideration. Variable consideration is included in the transaction price if, in the Company’s judgment, it is probable that a significant future reversal of cumulative revenue under the contract will not occur. Any estimates, including the effect of the constraint on variable consideration, are evaluated at each reporting period for any changes. Determining the transaction price requires significant judgment, which is discussed in further detail for each of the Company’s collaboration agreements in Note 5. In addition, neither of the Company’s contracts as of June 30, 2019 contained a significant financing component.

If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation on a relative standalone selling price basis unless the transaction price is variable and meets the criteria to be allocated entirely to a performance obligation or to a distinct service that forms part of a single performance obligation. The consideration to be received is allocated among the separate performance obligations based on relative standalone selling prices. The Company typically determines standalone selling prices using an adjusted market assessment approach model.

The Company satisfies performance obligations either over time or at a point in time. Revenue is recognized over time if either (i) the customer simultaneously receives and consumes the benefits provided by the entity’s performance, (ii) the entity’s performance creates or enhances an asset that the customer controls as the asset is created or enhanced, or (iii) the entity’s performance does not create an asset with an alternative use to the entity and the entity has an enforceable right to payment for performance completed to date. If the entity does not satisfy a performance obligation over time, the related performance obligation is satisfied at a point in time by transferring the control of a promised good or service to a customer.

As of June 30, 2019, the Company’s only revenue recognized is related to collaboration agreements with third parties which are either within the scope of ASC 606, under which the Company licenses certain rights to its product candidates to third parties, or within the scope of ASC 808, Collaborative Arrangements (“ASC 808”), if it involves a joint operating activity pursuant to which the Company is an active participant and is exposed to significant risks and rewards with respect to the arrangement. For the collaboration arrangements under the scope of ASC 606, as discussed in further detail in Note 5, the terms of these arrangements typically include payment to the Company of one or more of the following: nonrefundable, upfront fees; development, regulatory, and commercial milestone payments; research and development funding payments; and royalties on the net sales of licensed products. Each of these payments results in collaboration revenues, except for revenues from royalties on the net sales of licensed products, which are classified as royalty revenues. For arrangements within the scope of ASC 808, the terms of these arrangements typically include payments received or made under the cost sharing provisions which are recognized as a component of revenues in the condensed consolidated statements of operations and comprehensive loss.

Licenses of intellectual property: If the license to the Company’s IP is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from consideration allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the licenses. For licenses that are combined with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Milestone payments: At the inception of each arrangement that includes development milestone payments, the Company evaluates the probability of reaching the milestones and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur in the future, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received and therefore revenue recognized is constrained as management is unable to assert that a reversal of revenue would not be possible. The transaction price is then allocated to each performance obligation on a relative standalone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such development milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect collaboration revenues and earnings in the period of adjustment.

Royalties: For arrangements that include sales-based royalties, including milestone payments based on levels of sales, if the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its collaboration agreements.

The Company receives payments from its customers based on billing schedules established in each contract. The Company’s contract liabilities consist of deferred revenue. Upfront payments and fees are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company satisfies its obligations under these arrangements.

The Company also considers the nature and contractual terms of an arrangement and assesses whether the arrangement involves a joint operating activity pursuant to which the Company is an active participant and is exposed to significant risks and rewards with respect to the arrangement. If the Company is an active participant and is exposed to the significant risks and rewards with respect to the arrangement, the Company accounts for the arrangement under ASC 808. Based on this consideration, the Company accounts for its Co-Development and Co-Promotion Agreement (“Co/Co”) with Regeneron Pharmaceuticals, Inc. (“Regeneron”) under ASC 808. Because ASC 808 does not provide recognition and measurement guidance for collaborative arrangements, the Company has analogized to ASC 606. Refer to Note 5 for additional information regarding the Company’s collaboration agreements.

The following table presents changes in the Company’s contract liabilities during the six months ended June 30, 2019 and 2018 (in thousands):

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
Six Months Ended June 30, 2019
Contract liabilities:
Deferred revenue	$	55,932	$	2,000	$	(15,772	)	$	42,160

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
Six Months Ended June 30, 2018
Contract liabilities:
Deferred revenue	$	59,868	$	2,000	$	(11,009	)	$	50,859

During the six months ended June 30, 2019 and 2018, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands):

Revenue recognized in the period from:

Six Months Ended

June 30, 2019

Six Months Ended

June 30, 2018

Amounts included in the contract liability at the beginning of the period

15,772

11,009

Costs to obtain and fulfill a contract

The Company did not incur any expenses to obtain collaboration agreements and costs to fulfill those contracts do not generate or enhance resources of the Company. As such, no costs to obtain or fulfill a contract have been capitalized in any period.

Recent Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-02, Leases (“ASU 2016-02”). ASU 2016-02 established ASC 842, which amends ASC Topic 840, Leases, by introducing a lessee model that requires balance sheet recognition for most leases and the disclosure of key information about leasing arrangements. Leases will be classified as finance or operating, with classification affecting the pattern and classification of expense recognition in the income statement. ASC 842 was subsequently amended during 2018. The Company adopted the new standard using the required modified retrospective approach on January 1, 2019 and used the effective date as its date of initial application. As a result, prior periods are presented in accordance with the previous guidance in ASC Topic 840, Leases.

ASC 842 provides several optional practical expedients in transition. The Company elected the package of practical expedients which allows the Company to not reassess its existing conclusions on lease identification, classification, and initial direct costs. Further, the Company elected the hindsight practical expedient and utilized the short-term lease exemption for all leases with an original term of 12 months or less, for purposes of applying the recognition and measurement requirements of the new standard. The Company also elected the practical expedient which allows it to not separate lease and non-lease components for all its leases.

The adoption of the new standard on January 1, 2019 resulted in the recognition of operating lease liabilities of $20.6 million, and right-of-use assets of $22.3 million on the Company’s condensed consolidated balance sheet relating to its leases. Further, an adjustment to retained earnings of $0.3 million was recognized due to the use of hindsight being applied in updating the lease term for one of the Company’s property leases. The adoption of the standard did not have a material effect on the Company’s condensed consolidated statements of operations and comprehensive loss or condensed consolidated statements of cash flows.

Refer to Note 6, “Leases”, for the Company’s current lease commitments.

In June 2018, the FASB issued ASU 2018-07, Compensation—Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting, which simplifies the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments to employees, with certain exceptions. The Company’s adoption of the new standard beginning January 1, 2019 did not have a material effect on the Company’s condensed consolidated financial statements.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement, (“ASU 2018-13”). The new standard removes certain disclosures, modifies certain disclosures and adds additional disclosures related to fair value measurement. The new standard will be effective beginning January 1, 2020 and early adoption is permitted. The Company is currently evaluating the potential impact ASU 2018-13 may have on its disclosures upon adoption.

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Available-for-sale Marketable Securities

The following table summarizes the Company’s available-for-sale marketable securities as of June 30, 2019 and December 31, 2018 at net book value:

	June 30, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury securities	$	146,552	$	161	$	-		$	146,713
Financial institution debt securities		53,041		69		-			53,110
Corporate debt securities		18,892		-		-			18,892
Other asset-backed securities		7,958		25		-			7,983
Total	$	226,443	$	255	$	-		$	226,698

	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury securities	$	165,959	$	2	$	(13	)	$	165,948
Financial institution debt securities		65,436		1		(17	)		65,420
Corporate debt securities		23,836		-		(1	)		23,835
Total	$	255,231	$	3	$	(31	)	$	255,203

Summary of Changes in Contract Liabilities

The following table presents changes in the Company’s contract liabilities during the six months ended June 30, 2019 and 2018 (in thousands):

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
Six Months Ended June 30, 2019
Contract liabilities:
Deferred revenue	$	55,932	$	2,000	$	(15,772	)	$	42,160

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
Six Months Ended June 30, 2018
Contract liabilities:
Deferred revenue	$	59,868	$	2,000	$	(11,009	)	$	50,859

Summary of Revenues Recognized Resulting From Changes in Contract Liability Balance

During the six months ended June 30, 2019 and 2018, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands):

Revenue recognized in the period from:

Six Months Ended

June 30, 2019

Six Months Ended

June 30, 2018

Amounts included in the contract liability at the beginning of the period

15,772

11,009

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Marketable Securities

The following table summarizes the Company’s available-for-sale marketable securities as of June 30, 2019 and December 31, 2018 at net book value:

	June 30, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury securities	$	146,552	$	161	$	-		$	146,713
Financial institution debt securities		53,041		69		-			53,110
Corporate debt securities		18,892		-		-			18,892
Other asset-backed securities		7,958		25		-			7,983
Total	$	226,443	$	255	$	-		$	226,698

	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
Marketable securities:
U.S. Treasury securities	$	165,959	$	2	$	(13	)	$	165,948
Financial institution debt securities		65,436		1		(17	)		65,420
Corporate debt securities		23,836		-		(1	)		23,835
Total	$	255,231	$	3	$	(31	)	$	255,203

Leases

Revenue Recognition

The following table presents changes in the Company’s contract liabilities during the six months ended June 30, 2019 and 2018 (in thousands):

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
Six Months Ended June 30, 2019
Contract liabilities:
Deferred revenue	$	55,932	$	2,000	$	(15,772	)	$	42,160

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
Six Months Ended June 30, 2018
Contract liabilities:
Deferred revenue	$	59,868	$	2,000	$	(11,009	)	$	50,859

During the six months ended June 30, 2019 and 2018, the Company recognized the following revenues as a result of changes in the contract liability balance (in thousands):

Revenue recognized in the period from:

Six Months Ended

June 30, 2019

Six Months Ended

June 30, 2018

Amounts included in the contract liability at the beginning of the period

15,772

11,009

Costs to obtain and fulfill a contract

Recent Accounting Pronouncements

Refer to Note 6, “Leases”, for the Company’s current lease commitments.

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Collaboration revenue	$ 11,118	$ 7,677	$ 21,551	$ 15,146
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 25,460	$ 23,467	$ 49,169	$ 45,960
General and administrative	13,118	7,805	23,651	15,211
Total operating expenses	38,578	31,272	72,820	61,171
Operating loss	(27,460)	(23,595)	(51,269)	(46,025)
Interest income	1,777	1,376	3,646	2,450
Net loss	$ (25,683)	$ (22,219)	$ (47,623)	$ (43,575)
Net loss per share, basic and diluted	$ (0.56)	$ (0.52)	$ (1.05)	$ (1.03)
Weighted average shares outstanding, basic and diluted	45,814	42,836	45,526	42,441
Other comprehensive income:
Unrealized gain on marketable securities	$ 196		$ 283
Comprehensive loss	$ (25,487)	$ (22,219)	$ (47,340)	$ (43,575)

Leases

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Leases

6.Leases

In October 2014, the Company entered into an agreement to lease office and laboratory space at 130 Brookline Street in Cambridge, Massachusetts under an operating lease agreement with a term through January 2020, with an option to extend the term of the lease for an additional five-year period. In April 2019, the Company executed an amendment to the lease to extend the term of the lease for the additional five-year period, through January 2025. Upon the execution of the original lease, the Company provided a $0.3 million security deposit. The Company has recorded this security deposit in other assets on the condensed consolidated balance sheets.

In applying the ASC 842 transition guidance, the Company retained the classification of this lease as operating and recorded a lease liability and a right-of-use asset on the ASC 842 effective date with the five-year extension included in the lease term, based on the Company’s election of the hindsight practical expedient as the Company was reasonably certain to exercise this option term.

In March 2019, the Company entered into a separate agreement to sublease additional office and laboratory space at 130 Brookline Street in Cambridge, Massachusetts under an operating sublease agreement with a term through April 2021, with two options to extend the agreement by one year each, for a total option period of up to two years. Upon commencement of the lease in April 2019, the Company recognized a right-of-use asset and lease liability of approximately $1.3 million.

In January 2016, the Company entered into a ten-year agreement to lease office and laboratory space at 40 Erie Street in Cambridge, Massachusetts under an operating lease agreement, with an option to terminate the lease at the end of the sixth year and an option to extend the term of the lease for an additional three years. Upon the execution of this lease, the Company provided a $2.2 million security deposit, which has been recorded in other assets on the condensed consolidated balance sheets. In addition, the Company had prepaid $2.2 million in lease payments as of December 31, 2018 under the terms of this lease. In applying the ASC 842 transition guidance, the Company retained the classification of this lease as operating and recorded a lease liability and a right-of-use asset, based on the present value of the non-cancelable term, on the ASC 842 effective date.

Throughout the term of its leases, the Company is responsible for paying certain costs and expenses, in addition to the rent, as specified in the lease, including a proportionate share of applicable taxes, operating expenses and utilities. The variable portion of these costs are expensed as incurred and are disclosed as variable lease cost.

	Three Months Ended			Six Months Ended
	June 30, 2019
	(in thousands)
Lease cost
Operating lease cost	$	1,880		$	3,583
Variable lease cost		460			997
Total lease cost	$	2,340		$	4,580
Other information
Operating cash flows used for operating leases	$	1,635		$	3,122
Operating lease liabilities arising from obtaining right-of-use assets		1,343			1,343
Weighted average remaining lease term	3.5 years			3.5 years
Weighted average discount rate		9.00	%		9.00	%

Future minimum lease payments under the Company’s non-cancelable operating leases as of June 30, 2019, are as follows:

Future Operating Lease Payments
Year Ending December 31,	(in thousands)
2019 (excluding the six months ended June 30, 2019)	$	3,355
2020		6,483
2021		6,618
2022		4,732
2023		871
Thereafter		943
Total lease payments	$	23,002
Less: imputed interest		(3,333	)
Less: leases not yet commenced		-
Total operating lease liabilities at June 30, 2019	$	19,669

Future minimum lease payments under the Company’s non-cancelable operating leases as of December 31, 2018, are as follows:

Year Ending December 31,	(In thousands)
2019	$	5,616
2020		4,963
2021		5,507
2022		3,861
Thereafter		-
	$	19,947

Leases - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended				6 Months Ended
	Apr. 30, 2019	Mar. 31, 2019	Jan. 31, 2016	Oct. 31, 2014	Jun. 30, 2019	Dec. 31, 2018
Lessee Lease Description [Line Items]
Operating lease right-of-use assets					$ 20,923
Operating lease, liability					$ 19,669
130 Brookline Street [Member]
Lessee Lease Description [Line Items]
Operating lease, description					In October 2014, the Company entered into an agreement to lease office and laboratory space at 130 Brookline Street in Cambridge, Massachusetts under an operating lease agreement with a term through January 2020, with an option to extend the term of the lease for an additional five-year period. In April 2019, the Company executed an amendment to the lease to extend the term of the lease for the additional five-year period, through January 2025.
Operating lease expiration				2020-01
Lessee operating lease extended expiration date	Jan. 31, 2025
Operating lease, existence of option to extend				true
Operating lease, options to extend					option to extend the term of the lease for an additional five-year period. In April 2019, the Company executed an amendment to the lease to extend the term of the lease for the additional five-year period, through January 2025.
Operating lease, renewal term	5 years			5 years
Lessee operating sublease option to extend					two options to extend the agreement by one year each, for a total option period of up to two years.
Operating sublease expiration		2021-04
Operating sublease, existence of option to extend		true
Operating lease right-of-use assets	$ 1,300
Operating lease, liability	$ 1,300
130 Brookline Street [Member] \| Maximum [Member]
Lessee Lease Description [Line Items]
Operating sublease, renewal term		2 years
130 Brookline Street [Member] \| Other Assets [Member]
Lessee Lease Description [Line Items]
Lease security deposit				$ 300
40 Erie Street [Member]
Lessee Lease Description [Line Items]
Operating lease, description					In January 2016, the Company entered into a ten-year agreement to lease office and laboratory space at 40 Erie Street in Cambridge, Massachusetts under an operating lease agreement, with an option to terminate the lease at the end of the sixth year and an option to extend the term of the lease for an additional three years.
Operating lease, existence of option to extend			true
Operating lease, options to extend					option to extend the term of the lease for an additional three years.
Operating lease, renewal term			3 years
Operating lease, term of contract			10 years
Operating lease, existence of option to terminate			true
Operating lease, option to terminate					option to terminate the lease at the end of the sixth year
Operating lease, terminate term			6 years
Prepaid lease						$ 2,200
40 Erie Street [Member] \| Other Assets [Member]
Lessee Lease Description [Line Items]
Lease security deposit			$ 2,200

Stockholders Equity - Schedule of Changes in Stockholders Equity (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Class Of Stock [Line Items]
Beginning balance	$ 264,338	$ 277,920	$ 295,499	$ 300,597	$ 277,920	$ 300,597
Beginning balance, shares		45,224,480			45,224,480
Issuance of common stock through at-the-market offerings, net of issuance costs	31,413	$ 3,639
Exercise of stock options	1,664	360	557	6,720
Exercise of stock options, shares					233,872
Issuance of shares under employee stock purchase plan	534		598
Equity-based compensation	4,404	4,592	4,901	4,107
Other comprehensive gain	196	87
Net loss	(25,683)	(21,940)	(22,219)	(21,356)	$ (47,623)	(43,575)
Ending balance	$ 276,866	264,338	279,336	295,499	$ 276,866	279,336
Ending balance, shares	47,714,575				47,714,575
ASC 842 [Member]
Class Of Stock [Line Items]
Retroactive adjustment to beginning accumulated deficit		(320)
ASU 2014-09 [Member]
Class Of Stock [Line Items]
Retroactive adjustment to beginning accumulated deficit				5,431
Common Stock [Member]
Class Of Stock [Line Items]
Beginning balance	$ 5	$ 5	$ 4	$ 4	$ 5	$ 4
Beginning balance, shares	45,479,098	45,224,480	43,091,922	42,384,623	45,224,480	42,384,623
Issuance of common stock through at-the-market offering, net of issuance costs, shares	1,986,579	223,818
Exercise of stock options, shares	203,072	30,800	68,163	709,321
Issuance of shares under employee stock purchase plan, shares	45,826		32,707
Cancellation of restricted stock, shares			(4,780)	(2,022)
Ending balance	$ 5	$ 5	$ 4	$ 4	$ 5	$ 4
Ending balance, shares	47,714,575	45,479,098	43,188,012	43,091,922	47,714,575	43,188,012
Additional Paid-In Capital [Member]
Class Of Stock [Line Items]
Beginning balance	$ 487,559	$ 478,968	$ 432,533	$ 421,706	$ 478,968	$ 421,706
Issuance of common stock through at-the-market offerings, net of issuance costs	31,413	3,639
Exercise of stock options	1,664	360	557	6,720
Issuance of shares under employee stock purchase plan	534		598
Equity-based compensation	4,404	4,592	4,901	4,107
Ending balance	525,574	487,559	438,589	432,533	525,574	438,589
Accumulated Other Comprehensive Income (Loss) [Member]
Class Of Stock [Line Items]
Beginning balance	59	(28)			(28)
Other comprehensive gain	196	87
Ending balance	255	59			255
Accumulated Deficit [Member]
Class Of Stock [Line Items]
Beginning balance	(223,285)	(201,025)	(137,038)	(121,113)	(201,025)	(121,113)
Net loss	(25,683)	(21,940)	(22,219)	(21,356)
Ending balance	$ (248,968)	(223,285)	$ (159,257)	(137,038)	$ (248,968)	$ (159,257)
Accumulated Deficit [Member] \| ASC 842 [Member]
Class Of Stock [Line Items]
Retroactive adjustment to beginning accumulated deficit		$ (320)
Accumulated Deficit [Member] \| ASU 2014-09 [Member]
Class Of Stock [Line Items]
Retroactive adjustment to beginning accumulated deficit				$ 5,431

Collaborations

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Collaborations

5.	Collaborations

To accelerate the development and commercialization of CRISPR/Cas9-based products in multiple therapeutic areas, the Company has formed, and intends to seek other opportunities to form, strategic alliances with collaborators who can augment its leadership in CRISPR/Cas9 therapeutic development.

Novartis Institutes for BioMedical Research (“Novartis”)

In December 2014, the Company entered into a strategic collaboration agreement with Novartis, as amended, (the “2014 Novartis Agreement”) primarily focused on the development of new ex vivo CRISPR/Cas9-edited therapies using chimeric antigen receptor T (“CAR-T”) cells and hematopoietic stem cells (“HSCs”).

Agreement Structure. The parties agreed to engage in collaborative research activities using its CRISPR/Cas9 platform to identify and research therapeutic, prophylactic and palliative products and services relating to the following applications: a) ex vivo HSCs and b) ex vivo CAR-Ts. In addition, in the last two years of the collaboration term, Novartis may engage in research and development of a limited number of in vivo targets using the Company’s platform.

Scope of Collaboration. During the five-year collaboration term parties may research potential therapeutic, prophylactic and palliative ex vivo applications of the CRISPR/Cas9 technology in HSCs and CAR-T cells. Research expenses incurred by the Company in support of the collaboration are reimbursed by Novartis.

HSC Program. The Company and Novartis agreed to conduct research of HSC targets under a research plan agreed upon by both parties. Within the HSC therapeutic space, Novartis may obtain exclusive rights to a limited number of these HSC targets, to be selected by Novartis in a series of selection windows. The Company has the right to choose a limited number of HSC targets for its exclusive development and commercialization per the specified selection schedule. Following these selections by Novartis and the Company, Novartis may obtain rights to research an additional limited number of HSC targets on a non-exclusive basis. Novartis is required to use commercially reasonable efforts to research, develop and commercialize at least one HSC product directed to each of their selected HSC targets.

CAR-T Program. The Company has also agreed to collaborate with Novartis on research activities for CAR-T cell targets. After completion of the activities contemplated by the parties’ CAR-T cell program research plan, Novartis will assume sole responsibility for developing any products that it selects, arising from that research plan and the costs and expenses of developing, manufacturing and commercializing its selected research targets. Novartis is required to use commercially reasonable efforts to research, develop or commercialize at least one CAR-T cell product directed to each of its selected CAR-T cell targets.

In Vivo Program. During the last two years of the five-year collaboration term, Novartis has the option to select a limited number of targets for research, development and commercialization of in vivo therapies using the Company’s CRISPR/Cas9 platform, on a non-exclusive basis. Following Novartis’ selection of each in vivo target, Novartis may offer the Company the right to participate in the research and development of such targets, in which case an in vivo program research plan for such target will be entered into between the Company and Novartis. Novartis is required to use commercially reasonable efforts to research, develop or commercialize at least one in vivo product directed to each of its selected targets. Novartis’ in vivo target selections are subject to certain restrictions, including that the targets, or all targets within a limited number of organs: (i) have not already been reserved by the Company pursuant to its limited right to do so under the agreement; (ii) are not the subject of a collaboration or pending collaboration with a third party; and (iii) are not the subject of ongoing or planned research and development by the Company.

Governance. The parties formed HSC and CAR-T steering committees with responsibility for oversight of these respective research programs and approval of the associated research plans. Beginning in December 2018, the HSC steering committee became responsible for the ocular stem cell (“OSC”) program. These steering committees in turn are overseen by a joint steering committee. The above steering committees are comprised by an equal number of representatives from each party.

Financial Terms. The Company received an upfront technology access payment from Novartis of $10.0 million in January 2015 and was entitled to additional technology access fees of $20.0 million and quarterly research payments of $1.0 million, or up to $20.0 million in the aggregate, during the five-year research term. To date, the Company has received $20.0 million in technology access fees and $17.0 million in research payments related to these programs. In addition, for each Novartis product under the collaboration (whether HSC or CAR-T, and beginning as of December 2018, OSC), subject to certain conditions, the Company may be eligible to receive (i) up to $30.3 million in development milestones, including for the filing of an investigational new drug (“IND”) application and for the dosing of the first patient in each of Phase IIa, Phase IIb and Phase III clinical trials, (ii) up to $50.0 million in regulatory milestones for the product’s first indication, including regulatory approvals in the U.S. and European Union (“EU”), (iii) up to $50.0 million in regulatory milestones for the product’s second indication, if any, including U.S. and EU regulatory approvals, (iv) royalties on net sales in the mid-single digits, and (v) net sales milestone payments of up to $100.0 million. The Company is also eligible to receive payments for: (i) each additional HSC target selected by Novartis beyond its initial defined allocation, for which it will receive $1.0 million for each target, (ii) each in vivo target that Novartis selects as described above, and (iii) any exercise by Novartis of certain license options under the 2014 Novartis Agreement.

Upon completion of the research collaboration term in December 2019, Novartis has the option to internalize the Intellia platform for a $50.0 million fee, which will allow them to select a limited number of additional CRISPR/Cas9 genome editing targets over 5 years. Up to $20.0 million of the internalization fee will be credited towards any milestone payments for any additional post-internalization targets (up to $4.0 million per target).

Equity Investments. Additionally, at the inception of the arrangement, at which time the Company was a privately held company, Novartis invested $9.0 million to purchase the Company’s Class A-1 and Class A-2 Preferred Units. The difference between the cash proceeds received from Novartis for the units and the $11.6 million estimated fair value of those units at the date of issuance was determined to be $2.6 million. Accordingly, $2.6 million of the upfront technology access payment was allocated to record the preferred units purchased by Novartis at fair value.

License Grant to Novartis. In the 2014 Novartis Agreement, the Company granted to Novartis a license to its CRISPR/Cas9 platform technology, including a sublicense to certain platform rights licensed from Caribou Biosciences, Inc. (“Caribou”), that is exclusive in the HSC, CAR-T cell and in vivo fields with respect to each target selected by Novartis pursuant to the agreement and the research plan as long as Novartis continues to use commercially reasonable efforts to research, develop, and commercialize CRISPR-edited products directed to such targets. Upon the expiration of the collaboration term, Novartis shall have the option to access and obtain a non-exclusive license to the Company’s CRISPR/Cas9 platform technology to research, develop and commercialize potential therapeutic, prophylactic and palliative products and services for a limited number of certain approved targets selected by Novartis, exercisable upon written notice to the Company within 30 days after the expiration of the collaboration term. Such approved targets are subject to certain restrictions, including that the targets may not have been already reserved by the Company pursuant to its limited right to do so under the agreement, may not be the subject of an existing out license of the Company’s CRISPR/Cas9 platform to a third party and may not be the subject of ongoing or planned research and development by the Company. This non-exclusive license will have a term of five years commencing upon the completion of the technology transfer by the Company enabling Novartis to practice such licensed rights, and Novartis may not select more than a specified number of approved targets in each year of this license term.

License Grant to Intellia. Novartis granted the Company a non-exclusive license to its IP covering small molecule for HSC expansion and to its LNP platform technology to research, develop and commercialize HSC and in vivo genome editing products, respectively, in the 2014 Novartis Agreement.

Intellectual Property. IP that the Company develops within the collaboration related to the Company’s CRISPR/Cas9 platform will be owned solely by the Company, while all other IP developed within the collaboration, including IP covering products arising from the collaboration, will be jointly owned by the Company and Novartis.

2018 Amendment to the Agreement. In December 2018, the Company entered into an amendment to this agreement with Novartis (the “Novartis Amendment”) which expanded the scope of the 2014 Novartis Agreement to include the ex vivo development of CRISPR/Cas9-based cell therapies using limbal stem cells (“LSCs”), a type of OSC, primarily against gene targets selected by Novartis in exchange for a one-time payment of $10.0 million which the Company received in December 2018. The governance, milestones and royalties associated with any LSC program will follow those for the HSC programs. As part of the Novartis Amendment, Intellia rights to Novartis’ lipid nanoparticle (“LNP”) technology were expanded to include use on all genome editing applications in both in vivo and ex vivo settings.

Term and Termination. The collaboration term ends in December 2019. The term of the agreement expires on the later of (i) the expiration of Novartis’ payment obligations under the agreement and (ii) the date of expiration of the last-to-expire of the patent rights licensed to the Company or Novartis under the agreement. Novartis’ royalty payment obligations expire on a country-by-country and product-by-product basis upon the later of (i) the expiration of the last valid claim of the royalty-bearing patents covering such product in such country or (ii) 10 years after the first commercial sale of such product in such country. The Company may terminate the agreement if Novartis or its affiliates institute a patent challenge against its IP rights, and all improvements thereto, licensed to Novartis under the agreement. Novartis may terminate the agreement, without cause, upon 90 days’ written notice to the Company subject to certain conditions, including its payment of any accrued and future obligations as if the collaboration had continued through December 2019. Either party may terminate the agreement in the event of the other party’s uncured material breach or bankruptcy—or insolvency-related events.

Accounting Analysis. The Company has concluded that the 2014 Novartis Agreement and the Novartis Amendment are subject to ASC 606 and has assessed its accounting for them accordingly. The Company evaluated the promised goods and services under the 2014 Novartis Agreement and determined that it included two performance obligations: (1) a combined performance obligation representing a series of distinct goods and services including the licenses to research, develop and commercialize HSC products and their associated research activities and the licenses to research, develop and commercialize CAR-T cell products and their associated research activities; and (2) the preferred units.

The Company determined that the transaction price of the 2014 Novartis Agreement was $59.0 million consisting of the following consideration: (1) the upfront technology access payment of $10.0 million; (2) the additional technology access fees of $20.0 million; (3) the Company’s estimate of variable consideration of $20.0 million related to the quarterly research payments; and (4) the payment for the preferred units of $9.0 million. None of the clinical or regulatory milestones were included in the transaction price, as all milestone amounts were fully constrained. As part of its evaluation of the constraint, the Company considered numerous factors, including that receipt of the milestones is outside the control of the Company and contingent upon future regulatory progress and the licensee’s efforts. Any consideration related to sales-based milestones and royalties will be recognized when the related sales occur as they were determined to relate predominantly to the licenses granted to Novartis and therefore have also been excluded from the transaction price. The Company will re-evaluate the transaction price in each reporting period and when events whose outcomes are resolved or other changes in circumstances occur.

The Company first allocated $11.6 million of the transaction price to the preferred units to record the preferred units purchased by Novartis at fair value. The Company then allocated the remaining $47.4 million of the transaction price to the remaining combined performance obligation of the licenses and associated research activities for HSC and CAR-T cell products. Revenue allocated to the combined performance obligation of the licenses and associated research activities for HSC and CAR-T cell products is being recognized on a straight-line basis over a period of five years, which, in management’s judgment, is the best measure of progress towards satisfying the performance obligation and represents the Company’s best estimate of the period of the obligation.

The Company determined that there is only one combined performance obligation identified under the Novartis Amendment, representing a series of distinct goods and services including the licenses to research, develop and commercialize products using LSCs and their associated research and development services related to the research, development and commercialization of products using LSCs, and allocated the $10.0 million transaction price accordingly. Revenue allocated to this performance obligation is being recognized on a straight-line basis over a period of approximately one year, which, in management’s judgment, is the best measure of progress towards satisfying the performance obligation and represents the Company’s best estimate of the period of the obligation.

Revenue Recognition - Collaboration Revenue. Through June 30, 2019, excluding amounts allocated to Novartis’ purchase of the Company’s Class A-1 and Class A-2 Preferred Units, the Company had recorded a total of $55.4 million in cash and accounts receivable under the 2014 Novartis Agreement and the Novartis Amendment. Through June 30, 2019, the Company has recognized $48.4 million of collaboration revenue, including $4.8 million and $9.5 million during the three and six months ended June 30, 2019, respectively, and $2.4 million and $4.7 million during the three and six months ended June 30, 2018, respectively, in the condensed consolidated statements of operations and comprehensive loss related to the 2014 Novartis Agreement and the Novartis Amendment. As of June 30, 2019, there was approximately $9.0 million of the aggregate transaction price remaining to be recognized, which will be recognized through December 2019.

As of June 30, 2019 and December 31, 2018, the Company had accounts receivable of $1.0 million and $6.0 million, respectively, and deferred revenue of $7.0 million and $14.5 million, respectively, related to the 2014 Novartis Agreement and the Novartis Amendment.

Regeneron Pharmaceuticals, Inc.

In April 2016, the Company entered into a license and collaboration agreement with Regeneron (the “Regeneron Agreement”).

Agreement Structure. The Regeneron Agreement has two principal components: i) a product development component under which the parties will research, develop and commercialize CRISPR/Cas-based therapeutic products primarily focused on genome editing in the liver, and ii) a technology collaboration component, pursuant to which the Company and Regeneron will engage in research and development activities aimed at discovering and developing novel technologies and improvements to CRISPR/Cas technology to enhance the Company’s genome editing platform. Under this agreement, the Company also may access the Regeneron Genetics Center and proprietary mouse models to be provided by Regeneron for a limited number of the Company’s liver programs.

Scope of Collaboration. Under the terms of the six-year collaboration, Regeneron may obtain exclusive rights for up to 10 targets to be chosen by Regeneron during the collaboration term, subject to a target selection process and various adjustments and limitations set forth in the agreement. Of these 10 total targets, Regeneron may select up to five non-liver targets, while the remaining targets must be focused in the liver. Certain non-liver targets from the Company’s ongoing and planned research at the time, as well as any targets included in another of the Company’s collaborations, are excluded from this collaboration. At the inception of the agreement, Regeneron selected the first of its 10 targets, transthyretin amyloidosis (“ATTR”), which is subject to a Co/Co between the Company and Regeneron, the general terms and conditions for which were outlined within the Regeneron Agreement.

Research Collaboration. Research activities under the collaboration will be governed by evaluation and research and development plans that will outline the parties’ responsibilities under, anticipated timelines of and budgets for, the various programs. The Company will assist Regeneron with the preliminary evaluation of its selected liver targets, and Regeneron will be responsible for preclinical research and conducting clinical development, manufacturing and commercialization of products directed to each of its exclusive targets. The Company may assist, as requested by Regeneron, with the later discovery and research of product candidates directed to any selected target. For each selected target, Regeneron is required to use commercially reasonable efforts to submit regulatory filings necessary to achieve IND acceptance for at least one product directed to each applicable target, and following IND acceptance for at least one product, to develop and commercialize such product.

Reserved Liver Targets. The Company retains the exclusive right to solely develop products via CRISPR genome editing directed against certain specified genetic targets. During the collaboration term and subject to a target selection process, the Company has the right to choose additional liver targets for its own development using commercially reasonable efforts. Certain targets that either the Company or Regeneron select during the term may be subject to further co-development and co-commercialization arrangements at the Company or Regeneron’s option, as applicable, which either can exercise pursuant to defined conditions.

Governance. The parties formed a joint steering committee, which is responsible for setting research objectives and overseeing the general strategies and activities undertaken by the parties under the Regeneron Agreement. Additionally, the parties formed a Joint Development and Commercialization Committee (“JDCC”) to oversee all profit share products under the Co/Co discussed below. The JDCC will have responsibility for overseeing the development, manufacture, regulatory matters, and commercialization (including pricing and reimbursement) of ATTR, as the first profit share product under the collaboration agreement.

Financial Terms. The Company received a nonrefundable upfront payment of $75.0 million. In addition, on Regeneron programs that are not subject to co-development and co-promotion agreements the Company may be eligible to earn, on a per-licensed target basis, (i) up to $25.0 million in development milestones, including for the dosing of the first patient in each of Phase I, Phase II and Phase III clinical trials, (ii) up to $110.0 million in regulatory milestones, including for the acceptance of a regulatory filing in the U.S., and for obtaining regulatory approval in the U.S. and in certain other identified countries, and (iii) up to $185.0 million in sales-based milestone payments. The Company is also eligible to earn royalties ranging from the high single digits to low teens, in each case, on a per-product basis, which royalties are potentially subject to various reductions and offsets and incorporate the Company’s existing low- to mid-single-digit royalty obligations under a license agreement with Caribou. In addition, Regeneron is obligated to fund 50.0 percent of the research and development costs for the ATTR program.

Equity Investments. In connection with this collaboration, Regeneron purchased $50.0 million of the Company’s common stock in a private placement under a Stock Purchase Agreement concurrent with the Company’s initial public offering.

Term and Termination. The collaboration term ends in April 2022, except that Regeneron may make a one-time payment of $25.0 million to extend the term for an additional two-year period. The agreement will continue until the date when no royalty or other payment obligations are due, unless earlier terminated in accordance with the terms of the agreement. Regeneron’s royalty payment obligations expire on a country-by-country and product-by-product basis upon the later of (i) the expiration of the last valid claim of the royalty-bearing patents covering such product in such country, (ii) 12 years from the first commercial sale of such product in such country, or (iii) the expiration of regulatory exclusivity for such product. The Company may terminate the agreement on a target-by-target basis if Regeneron does not proceed with the development of a product directed to a selected target within specified periods of time. Regeneron may terminate the agreement, without cause, upon 180 days written notice to the Company, either in its entirety or on a target-by-target basis, in which event, certain rights in the terminated targets and associated IP revert to the Company, as described in the agreement. Following such termination, the Company may owe Regeneron royalties, in certain circumstances, up to mid-single digits on any terminated targets that the Company subsequently commercializes on a product-by-product basis for a period of 12 years after the first commercial sale of any such products. Either party may terminate the agreement either in its entirety or with respect to the technology collaboration or one or more of the targets selected by Regeneron, in the event of the other party’s uncured material breach.

Co-Development and Co-Promotion Agreement. In July 2018, the Company and Regeneron finalized the form of the Co/Co that will be used as the basis for each Co/Co agreement directed to a target. Simultaneously, the Company and Regeneron executed the Co/Co agreement directed to the first collaboration target, ATTR, for which the Company will be the clinical and commercial Lead Party (see below). As such, Regeneron will be the Participating Party (see below) and will share equally in worldwide development costs and profits as long as it funds half of the defined research and development costs attributable to the ATTR program.

Co-Development and Co-Promotion: Agreement Structure. Under the Co/Co agreement, Regeneron has the right to exercise up to at least five Co/Co options on the Company’s liver targets (other than the Company’s reserved liver targets), while the Company may exercise at least one Co/Co option on Regeneron’s liver targets, the exact number of Co/Co options being subject to certain conditions of the target selection process. Co/Co options must be exercised (or forfeited) once a target reaches a defined preclinical stage. Within 15 days of exercising the Co/Co option, the party exercising the option must pay $1.5 million to the other party as compensation for prior work. The ATTR program was exempted from this payment. One Party will be the “Lead Party” and the other Party the “Participating Party”. The Lead Party shall have control and primary responsibility for the development, manufacturing, regulatory and commercial activities. The Participating Party shall have the right to consult on these activities through its participation on the JDCC and will have the right to co-fund development and commercialization activities in exchange for a share of profits. In general, the parties will share equally in worldwide development costs and profits of any future products. Prior to reaching a specific development milestone, the Participating Party may elect to reduce its share of worldwide development costs and profits by 50.0 percent.

Co-Development and Co-Promotion: Termination. Either party may terminate by providing 180 days written notice. If the Company terminates, the product becomes a Regeneron product, and is subject to all future milestone and royalty payment obligations under the Regeneron agreement. If Regeneron terminates and has contributed at least $5.0 million in development costs, the Company will pay low- to mid-single digit royalties on the net sales of the product, depending on co-funding percentage, stage at termination, if any, and Regeneron IP incorporated into the product.

Accounting Analysis. The Company determined that the Regeneron Agreement is within the scope of ASC 606. The Company evaluated the promised goods and services under the Regeneron Agreement and determined that the Regeneron Agreement included three performance obligations: (1) a combined performance obligation including the licenses to targets and the associated research activities and evaluation plans; (2) a combined performance obligation including the technology collaboration and associated research activities; and (3) the common stock.

The Company also concluded that the ATTR Co/Co meets the definition of a collaborative arrangement per ASC 808, which is outside of the scope of ASC 606. Since ASC 808 does not provide recognition and measurement guidance for collaborative arrangements, the Company has analogized to ASC 606. As such, the Company classifies payments received or made under the cost sharing provisions of the ATTR Co/Co as a component of revenues in the condensed consolidated statements of operations and comprehensive loss.

Under the Regeneron Agreement, the Company determined that the transaction price was $125.0 million, consisting of the following consideration: (1) the nonrefundable upfront payment of $75.0 million; and (2) the payment for the common stock of $50.0 million. None of the clinical or regulatory milestones were included in the transaction price, as all milestone amounts were fully constrained. As part its evaluation of the constraint, the Company considered numerous factors, including that receipt of the milestones is outside the control of the Company and contingent upon success in future regulatory progress and the licensee’s efforts. Any consideration related to sales-based milestones and royalties will be recognized when the related sales occur as they were determined to relate predominantly to the licenses granted to Regeneron and therefore have also been excluded from the transaction price. The Company will re-evaluate the transaction price in each reporting period and when events whose outcome are resolved or other changes in circumstances occur.

The Company first allocated $50.0 million of the transaction price to the common stock. The common stock was sold at its standalone selling price and the Company concluded that the total discount inherent in the arrangement is entirely attributable to the combined performance obligation including the licenses to targets and associated research activities and evaluation plans and the combined performance obligation including the technology collaboration and associated research activities. As such, the remaining $75.0 million of the transaction price was allocated to the combined performance obligation including the licenses to targets and associated research activities and evaluation plans and the combined performance obligation including the technology collaboration and associated research activities on a relative standalone selling price basis. The Company estimated the standalone selling price of each combined performance obligation by taking into consideration internal estimates of research and development personnel needed to perform the research and development services, estimates of expected cash outflows to third parties for services and supplies, selling prices of comparable transactions and typical gross profit margins. As a result of this evaluation, the Company allocated $63.8 million to the combined performance obligation including the licenses to targets and associated research activities and evaluation plans and $11.2 million to the combined performance obligation including the technology collaboration and associated research activities. The $63.8 million allocated to the combined performance obligation including the licenses to targets and associated research activities and evaluation plans is being recognized on a straight-line basis over the six-year performance period of the arrangement, which, in management’s judgment, is the best measure of progress

towards satisfying the performance obligation and represents the Company’s best estimate of the period of the obligation. The $11.2 million allocated to the combined performance obligation including the technology collaboration and associated research activities is being recognized on a straight-line basis over a period beginning with the inception of the technology collaboration in September 2016 through the end of the arrangement, which, in management’s judgment, is the best measure of progress towards satisfying the performance obligation and represents the Company’s best estimate of the period of the obligation.

Revenue Recognition – Collaboration Revenue. Through June 30, 2019, excluding the amounts allocated to Regeneron’s purchase of the Company’s common stock, the Company recorded a $75.0 million upfront payment and $17.9 million for research and development services under the Regeneron Agreement. Through June 30, 2019, the Company has recognized $57.7 million of collaboration revenue, including $6.3 million and $12.0 million during the three and six months ended June 30, 2019, respectively, and $5.3 million and $10.4 million during the three and six months ended June 30, 2018, respectively, in the condensed consolidated statements of operations and comprehensive loss related to this arrangement. This includes $3.2 million and $5.8 million during the three and six months ended June 30, 2019, respectively, and $2.1 million and $4.1 million during the three and six months ended June 30, 2018, respectively, representing payments due from Regeneron pursuant to the ATTR Co/Co, which is accounted for under ASC 808. As of June 30, 2019, there was approximately $35.2 million of the aggregate transaction price remaining to be recognized, which will be recognized ratably through April 2022.

As of June 30, 2019 and December 31, 2018, the Company had accounts receivable of $3.2 million and $1.5 million, respectively, and deferred revenue of $35.2 million and $41.4 million, respectively, related to this arrangement.

Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized equity-based compensation expense related to restricted stock	$ 0.8		$ 0.8
Weighted average grant date fair value per share	$ 9.22	$ 16.64	$ 9.07	$ 17.94
Unrecognized compensation cost related to stock options	$ 34.1		$ 34.1
Unvested restricted stock outstanding	72,611		72,611		109,073
Stock options outstanding	5,315,496		5,315,496		5,037,663
Vesting description			The performance-based restricted stock units and performance-based stock options vest upon obtaining certain scientific, financial and regulatory milestones through 2020
Potential dilutive securities excluded from computation of diluted net loss per common share			5,388,000	5,142,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period of unrecognized compensation costs			1 year 4 months 24 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period of unrecognized compensation costs			2 years 7 months 6 days
Performance Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock outstanding	71,875		71,875
Potential dilutive securities excluded from computation of diluted net loss per common share			71,875
Performance Based Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options outstanding	213,750		213,750
Potential dilutive securities excluded from computation of diluted net loss per common share			188,750

Equity-Based Compensation

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Equity-Based Compensation

7.	Equity-Based Compensation

Equity-based compensation expense is classified in the condensed consolidated statements of operations and comprehensive loss as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
	(In thousands)
Research and development	$	2,096	$	2,633	$	3,879	$	5,026
General and administrative		2,308		2,268		5,117		3,982
Total	$	4,404	$	4,901	$	8,996	$	9,008

Restricted Stock

Restricted stock is measured at fair value based on the quoted price of the Company’s common stock.

The following table summarizes the Company’s restricted stock activity for the six months ended June 30, 2019:

	Number of Shares			Weighted Average Grant Date Fair Value per Share
Unvested restricted stock as of December 31, 2018		109,073		$	15.53
Granted		-			-
Vested		(36,462	)		1.34
Cancelled		-			-
Unvested restricted stock as of June 30, 2019		72,611		$	22.66

As of June 30, 2019, there was $0.8 million of unrecognized equity-based compensation expense related to restricted stock that is expected to vest. These costs are expected to be recognized over a weighted average remaining vesting period of 1.4 years.

Stock Options

The weighted average grant date fair value of options, estimated as of the grant date using the Black-Scholes option pricing model, was $9.22 and $9.07 per option for those options granted during the three and six months ended June 30, 2019, respectively, and $16.64 and $17.94 per option for those options granted during the three and six months ended June 30, 2018, respectively. Key assumptions used to apply this pricing model were as follows:

	Three Months Ended June 30,		Six Months Ended June 30,
	2019	2018	2019	2018
Risk-free interest rate	2.1%	2.8%	2.4%	2.6%
Expected life of options	5.5-6.0 years	5.5-6.25 years	5.5-6.0 years	5.5-6.25 years
Expected volatility of underlying stock	67.9%	87.7%	68.6%	89.0%
Expected dividend yield	0.0%	0.0%	0.0%	0.0%

The following is a summary of stock option activity for the six months ended June 30, 2019:

	Number of Options			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(In years)		(In thousands)
Outstanding at December 31, 2018		5,037,663		$	15.63
Granted		793,813			14.54
Exercised		(233,872	)		8.65
Forfeited		(282,108	)		18.79
Outstanding at June 30, 2019		5,315,496		$	15.61		8.14	$	14,978
Exercisable at June 30, 2019		2,165,526		$	13.43		7.01	$	10,193

As of June 30, 2019, there was $34.1 million of unrecognized compensation cost related to stock options that are expected to vest. These costs are expected to be recognized over a weighted average remaining vesting period of 2.6 years.

Of the unvested restricted stock outstanding and stock options outstanding as of June 30, 2019, 71,875 are performance-based restricted stock units and 213,750 are performance-based stock options. The performance-based restricted stock units and performance-based stock options vest upon obtaining certain scientific, financial and regulatory milestones through 2020. At June 30, 2019, 71,875 performance-based restricted stock units and 188,750 performance-based options are not included in computing the diluted (loss) earnings per share because the performance criteria had not been met as of the end of the reporting period.

Overview and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	6 Months Ended	62 Months Ended
	Jul. 02, 2019	Oct. 12, 2018	Nov. 30, 2018	Jun. 30, 2019	Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering				$ 7,912	$ 580,200
Proceeds from issuance of convertible preferred stock					85,000
Proceeds due from at-the-market offerings				27,140	27,140
Collaborative Arrangement [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering					$ 146,700
Sales Agreement [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering			$ 28,500	$ 35,200
Percentage of gross proceeds from common stock as sales agent cash commission		3.00%	3.00%	3.00%
Number of common stock issued upon conversion of shares			1,659,300	2,210,397
Common stock price per share			$ 18.00	$ 16.41	$ 16.41
Sales Agreement [Member] \| General and Administrative Expenses [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Legal accounting and other fees			$ 400	$ 100
Sales Agreement [Member] \| Maximum [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering		$ 100,000
Initial Public Offering and Concurrent Private Placements [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering					$ 170,500
Follow-on public Offering [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering					141,000
At-the-market Offering [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering					$ 37,000
At-the-market Offering [Member] \| Subsequent Event [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Proceeds from common stock offering	$ 27,100

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Realized loss on marketable securities	$ 0
Expenses incurred to obtain collaboration agreements and costs to fulfill contracts	0
Costs to obtain or fulfill contract capitalized	0
Operating lease, liability	19,669,000
Operating lease right-of-use assets	20,923,000
Retained earnings	$ (248,968,000)		$ (201,025,000)
ASU 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating lease, liability		$ 20,600,000
Operating lease right-of-use assets		22,300,000
ASU 2016-02 [Member] \| Restatement Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Retained earnings		$ 300,000

Equity-Based Compensation - Summary of Restricted Stock Activity (Detail)	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Unvested, Beginning balance \| shares	109,073
Number of Shares, Vested \| shares	(36,462)
Number of Shares, Unvested, Ending balance \| shares	72,611
Weighted Average Grant Date Fair Value per Share, Unvested, Beginning balance \| $ / shares	$ 15.53
Weighted Average Grant Date Fair Value per Share, Vested \| $ / shares	1.34
Weighted Average Grant Date Fair Value per Share, Unvested, Ending balance \| $ / shares	$ 22.66

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued legal and professional expenses	$ 4,837	$ 1,633
Accrued employee compensation and benefits	3,803	6,175
Accrued research and development	2,485	2,328
Accrued other	773	606
Total accrued expenses	$ 11,898	$ 10,742

Leases - Schedule of Future Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Leases [Abstract]
2019 (excluding the six months ended June 30, 2019)	$ 3,355
2019		$ 5,616
2020	6,483	4,963
2021	6,618	5,507
2022	4,732	3,861
2023	871
Thereafter	943
Total lease payments	23,002	$ 19,947
Less: imputed interest	(3,333)
Operating lease, liability	$ 19,669

Loss Per Share - Potential Dilutive Securities Excluded from Computation of Diluted Net Loss Per Common Share (Detail) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	5,388	5,142
Unvested Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	73	261
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities excluded from computation of diluted net loss per common share	5,315	4,881

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	120,000,000	120,000,000
Common stock, shares issued	47,714,575	45,224,480
Common stock, shares outstanding	47,714,575	45,224,480

Summary of Significant Accounting Policies - Summary of Available -for-sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Marketable Securities [Line Items]
Amortized Cost	$ 226,443	$ 255,231
Gross Unrealized Gains	255	3
Gross Unrealized Losses		(31)
Estimated Fair Value	226,698	255,203
U.S. Treasury Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	146,552	165,959
Gross Unrealized Gains	161	2
Gross Unrealized Losses		(13)
Estimated Fair Value	146,713	165,948
Financial Institution Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	53,041	65,436
Gross Unrealized Gains	69	1
Gross Unrealized Losses		(17)
Estimated Fair Value	53,110	65,420
Corporate Debt Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	18,892	23,836
Gross Unrealized Losses		(1)
Estimated Fair Value	18,892	$ 23,835
Other Asset Backed Securities [Member]
Marketable Securities [Line Items]
Amortized Cost	7,958
Gross Unrealized Gains	25
Estimated Fair Value	$ 7,983

Leases - Summary of Lease Costs and Other Information (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Lease cost
Operating lease cost	$ 1,880	$ 3,583
Variable lease cost	460	997
Total lease cost	2,340	4,580
Other information
Operating cash flows used for operating leases	1,635	3,122
Operating lease liabilities arising from obtaining right-of-use assets	$ 1,343	$ 1,343
Weighted average remaining lease term	3 years 6 months	3 years 6 months
Weighted average discount rate	9.00%	9.00%

Summary of Significant Accounting Policies - Summary of Revenues Recognized Resulting From Changes in Contract Liability Balance (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Revenue From Contract With Customer [Abstract]
Amounts included in the contract liability at the beginning of the period	$ 15,772	$ 11,009

Fair Value Measurements - Summary of Financial Assets Recognized at Fair Value on Recurring Basis (Detail) - Fair Value on Recurring Basis [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 45,799	$ 45,986
Marketable securities:
Marketable securities	226,698	255,203
Total	272,497	301,189
U.S. Treasury Securities [Member]
Marketable securities:
Marketable securities	146,713	165,948
Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities	53,110	65,420
Corporate Debt Securities [Member]
Marketable securities:
Marketable securities	18,892	23,835
Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities	7,983
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	45,799	45,986
Marketable securities:
Marketable securities	146,713	165,948
Total	192,512	211,934
Level 1 [Member] \| U.S. Treasury Securities [Member]
Marketable securities:
Marketable securities	146,713	165,948
Level 2 [Member]
Marketable securities:
Marketable securities	79,985	89,255
Total	79,985	89,255
Level 2 [Member] \| Financial Institution Debt Securities [Member]
Marketable securities:
Marketable securities	53,110	65,420
Level 2 [Member] \| Corporate Debt Securities [Member]
Marketable securities:
Marketable securities	18,892	$ 23,835
Level 2 [Member] \| Other Asset Backed Securities [Member]
Marketable securities:
Marketable securities	$ 7,983

Summary of Significant Accounting Policies - Summary of Changes in Contract Liabilities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Contract liabilities:
Deferred revenue, Balance at Beginning of Period	$ 55,932	$ 59,868
Deferred revenue, Additions	2,000	2,000
Deferred revenue, Deductions	(15,772)	(11,009)
Deferred revenue, Balance at End of Period	$ 42,160	$ 50,859