Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Total revenues	$ 63,069	$ 52,283	$ 125,409	$ 101,665
Cost and expenses
Cost of product revenues	39,204	33,709	78,259	66,797
Research and development	11,852	11,786	26,192	24,436
Selling, general and administrative	37,440	34,309	75,365	71,891
Total cost and expenses	90,287	80,654	183,144	164,586
Loss from operations	(27,218)	(28,371)	(57,735)	(62,921)
Interest expense	(2,560)	(218)	(4,949)	(401)
Interest and other (expense) income, net	(3,933)	(413)	(3,796)	887
Loss before income taxes	(33,711)	(29,002)	(66,480)	(62,435)
Income tax expense	(113)	(64)	(217)	(111)
Net loss	(33,824)	(29,066)	(66,697)	(62,546)
Unrealized gain (loss) on available-for-sale securities, net of tax	46	62	(92)	262
Comprehensive loss	$ (33,778)	$ (29,004)	$ (66,789)	$ (62,284)
Net loss per share (Note 12):
Basic (in dollars per share)	$ (0.62)	$ (0.55)	$ (1.23)	$ (1.18)
Diluted (in dollars per share)	$ (0.62)	$ (0.55)	$ (1.23)	$ (1.18)
Weighted-average number of shares used in computing basic and diluted net loss per share:
Basic (in shares)	54,551	53,088	54,342	52,924
Diluted (in shares)	54,551	53,088	54,342	52,924
Product
Revenues
Total revenues	$ 60,353	$ 50,929	$ 114,622	$ 99,323
Licensing and other
Revenues
Total revenues	2,716	1,354	10,787	2,342
Cost and expenses
Cost of product revenues	$ 1,791	$ 850	$ 3,328	$ 1,462