Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue:
Product and service	$ 17,488	$ 12,498	$ 29,624	$ 23,330
Collaboration	5,139	568	7,700	1,329
Total revenue	22,627	13,066	37,324	24,659
Costs and expenses:
Cost of product and service revenue	7,871	5,871	13,741	11,211
Research and development	8,799	5,798	16,007	11,714
Selling, general and administrative	15,507	12,823	30,411	26,948
Total costs and expenses	32,177	24,492	60,159	49,873
Loss from operations	(9,550)	(11,426)	(22,835)	(25,214)
Other income (expense):
Interest income	94	56	162	123
Interest expense	(1,326)	(1,001)	(2,641)	(1,985)
Other income (expense), net	12	(33)	(59)	(222)
Total other income (expense), net	(1,220)	(978)	(2,538)	(2,084)
Net loss before provision for income tax	(10,770)	(12,404)	(25,373)	(27,298)
Provision for income tax	(35)	0	(35)	0
Net loss	$ (10,805)	$ (12,404)	$ (25,408)	$ (27,298)
Net loss per share - basic and diluted (in dollars per share)	$ (0.55)	$ (0.66)	$ (1.29)	$ (1.47)
Weighted average shares used in computing basic and diluted net loss per share (in shares)	19,803	18,831	19,736	18,572