Statements of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Collaborative research and development and other revenue	$ 1,880	$ 7,832	$ 8,256
Product revenue, net	12,145	11,292	11,145
Total revenues	14,025	19,124	19,401
Operating expenses:
Cost of product revenues	5,290	3,905	5,686
Research and development	29,274	24,317	22,429
Selling, general and administrative	11,825	11,566	12,284
Total operating expenses	46,389	39,788	40,399
Loss from operations	(32,364)	(20,664)	(20,998)
Other income (expense):
Interest and other income	143	237	39
Interest expense	(2,288)	(2,236)	(1,151)
Net other income (expense)	(2,145)	(1,999)	(1,112)
Net loss	(34,509)	(22,663)	(22,110)
Net change in unrealized gain (loss) on available-for-sale securities, net of tax	11	(101)	86
Total comprehensive loss	$ (34,498)	$ (22,764)	$ (22,024)
Net loss per share
Basic	$ (0.26)	$ (0.19)	$ (0.20)
Diluted	$ (0.26)	$ (0.19)	$ (0.20)
Weighted-average shares used in computing net loss per share
Basic	133,163	118,523	111,666
Diluted	133,163	118,523	111,666