Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Total revenues	$ 65,280	$ 55,910	$ 190,689	$ 157,575
Cost and expenses
Cost of revenues	39,477	33,558	117,736	100,355
Research and development	12,393	12,609	38,585	37,045
Selling, general and administrative	38,374	34,478	113,739	106,369
Total cost and expenses	92,446	81,699	275,590	246,285
Loss from operations	(27,166)	(25,789)	(84,901)	(88,710)
Interest expense	(2,781)	(1,477)	(7,730)	(1,878)
Interest and other income (expense), net	449	(437)	(3,347)	450
Loss before income taxes	(29,498)	(27,703)	(95,978)	(90,138)
Income tax expense	(118)	(162)	(335)	(273)
Net loss	(29,616)	(27,865)	(96,313)	(90,411)
Unrealized (loss) gain on available-for-sale securities, net of tax	(36)	67	(128)	329
Comprehensive loss	$ (29,652)	$ (27,798)	$ (96,441)	$ (90,082)
Net loss per share (Note 12):
Basic (in dollars per share)	$ (0.49)	$ (0.52)	$ (1.71)	$ (1.70)
Diluted (in dollars per share)	$ (0.49)	$ (0.52)	$ (1.71)	$ (1.70)
Weighted-average number of shares used in computing basic and diluted net loss per share:
Basic (in shares)	60,570	53,447	56,462	53,100
Diluted (in shares)	60,570	53,447	56,462	53,100
Product
Revenues
Total revenues	$ 62,662	$ 54,512	$ 177,284	$ 153,835
Licensing and other
Revenues
Total revenues	2,618	1,398	13,405	3,740
Cost and expenses
Cost of revenues	$ 2,202	$ 1,054	$ 5,530	$ 2,516