Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Revenue	$ 30,345	$ 24,999	$ 58,033	$ 48,084
Costs and expenses:
Cost of product and service revenue	9,605	8,552	18,314	16,247
Research and development	17,029	14,585	33,056	28,417
Selling, general and administrative	22,499	20,649	45,935	40,086
Total costs and expenses	49,133	43,786	97,305	84,750
Loss from operations	(18,788)	(18,787)	(39,272)	(36,666)
Other income (expense):
Interest income	828	204	1,351	442
Interest expense	(1,889)	(1,604)	(3,637)	(3,167)
Other expense, net	(120)	(349)	(230)	(284)
Total other expense, net	(1,181)	(1,749)	(2,516)	(3,009)
Net loss before provision for income tax	(19,969)	(20,536)	(41,788)	(39,675)
Provision for income tax	(68)	(65)	(147)	(128)
Net loss	$ (20,037)	$ (20,601)	$ (41,935)	$ (39,803)
Net loss per share - basic and diluted (in dollars per share)	$ (0.57)	$ (0.80)	$ (1.26)	$ (1.55)
Weighted average shares used in computing basic and diluted net loss per share (in shares)	35,174	25,757	33,382	25,619
Total product and service revenue
Revenue:
Revenue	$ 22,370	$ 20,384	$ 43,720	$ 38,429
Collaboration revenue
Revenue:
Revenue	$ 7,975	$ 4,615	$ 14,313	$ 9,655