Organization, Basis of Presentation and Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2018

Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the statement of financial position that sum to the total of the same amounts in the statement of cash flows:

	As of  September 30,
(in thousands)	2018		2017
Cash and cash equivalents	$	39,298	$	29,894
Restricted cash included in other non-current assets		79,941		—
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$	119,239	$	29,894

Topic 606 [Member]

Summary of Financial Statement Line Item Affected Cumulative Adjustment and Compared with Guidance in Effect Prior to Adoption

Refer below for a summary of the amount by which each financial statement line item was affected by the impact of the cumulative adjustment and as compared with the guidance that was in effect prior to the adoption:

	Impact of Topic 606 Adoption on Condensed Consolidated Balance Sheet as of January 1, 2018
(in thousands)	As reported under Topic 606			Adjustments			Balances without adoption of Topic 606
Deferred revenue, current portion	$	29,626		$	1,281		$	28,345
Deferred revenue, noncurrent portion	$	26,846		$	(2,398	)	$	29,244
Accumulated deficit	$	(494,362	)	$	1,117		$	(495,479	)

	Impact of Topic 606 Adoption on Condensed Consolidated Balance Sheet as of September 30, 2018
(in thousands)	As reported under Topic 606			Adjustments			Balances without adoption of Topic 606
Deferred revenue, current portion	$	51,094		$	12,741		$	63,835
Deferred revenue, noncurrent portion	$	123,917		$	(3,130	)	$	120,787
Accumulated deficit	$	(544,032	)	$	(9,611	)	$	(553,643	)

	Impact of Topic 606 Adoption on Condensed Consolidated Statement of Operations and Comprehensive Loss for the Three Months Ended September 30, 2018									Impact of Topic 606 Adoption on Condensed Consolidated Statement of Operations and Comprehensive Loss for the Nine Months Ended September 30, 2018
(in thousands)	As reported under Topic 606			Adjustments			Balances without adoption of Topic 606			As reported under Topic 606			Adjustments			Balances without adoption of Topic 606
Collaboration revenue	$	23,538		$	(4,461	)	$	19,077		$	57,378		$	(8,495	)	$	48,883
Net loss	$	(12,843	)	$	(4,461	)	$	(17,304	)	$	(49,670	)	$	(8,495	)	$	(58,165	)
Net loss per share - basic and diluted:	$	(0.13	)	$	(0.04	)	$	(0.17	)	$	(0.52	)	$	(0.09	)	$	(0.61	)

	Impact of Topic 606 Adoption on Condensed Consolidated Statement of Cash Flows for the Nine Months Ended September 30, 2018
(in thousands)	As reported under Topic 606			Adjustments			Balances without adoption of Topic 606
Net loss	$	(49,670	)	$	(8,495	)	$	(58,165	)
Changes in deferred revenue	$	118,540		$	8,495		$	127,035