Summary of significant accounting policies (Tables)

9 Months Ended

Sep. 30, 2018

ASU 2014-09

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Schedule of impact of adoption of financial statement line items shows comparative balances under ASC 606 and ASC 605

Condensed Consolidated Statements of Operations and Comprehensive Loss

	Three months ended September 30, 2018
	Under ASC 606		Under ASC 605		Effect of change
	(in thousands, except per share data)
Collaboration revenue	$	2,094	$	3,054	$	(960)
Loss before income taxes		(20,289)		(19,329)		(960)
Net loss		(20,289)		(19,329)		(960)
Net loss per share, basic and diluted		(0.63)		(0.60)		(0.03)

	Nine months ended September 30, 2018
	Under ASC 606		Under ASC 605		Effect of change
	(in thousands, except per share data)
Collaboration revenue	$	5,611	$	7,267	$	(1,656)
Loss before income taxes		(65,937)		(64,281)		(1,656)
Net loss		(65,757)		(64,101)		(1,656)
Net loss per share, basic and diluted		(2.06)		(2.00)		(0.06)

Condensed Consolidated Balance Sheets

	As of September 30, 2018
	Under ASC 606		Under ASC 605		Effect of change
	(in thousands)
Deferred revenue, current	$	20,250	$	19,078	$	1,172
Deferred revenue, non-current		94,804		74,390		20,414
Accumulated deficit		(246,520)		(224,934)		(21,586)

Condensed Consolidated Statements of Cash Flows

	Nine months ended September 30, 2018
	Under ASC 606		Under ASC 605		Effect of change
	(in thousands)
Net loss	$	(65,757)	$	(64,101)	$	(1,656)
Adjustments to reconcile net loss to net cash provided by operating activities:
Deferred revenue		63,388		61,732		1,656