Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Revenue	$ 117,316	$ 125,568	$ 106,732
Total revenue	117,316	125,568	106,732
Costs and expenses:
Cost of product and service revenue	52,409	44,039	36,331
Research and development	62,857	68,035	61,599
Selling, general and administrative	90,097	96,195	78,195
Total costs and expenses	205,363	208,269	176,125
Loss from operations	(88,047)	(82,701)	(69,393)
Other income (expense):
Gain on sale of business, net	0	48,871	0
Loss on extinguishment of debt and termination of revolving loan facility	(7,143)	0	0
Interest income	1,744	2,819	1,331
Interest expense	(15,408)	(8,487)	(7,431)
Other expense, net	(971)	(929)	(1,658)
Total other income (expense), net	(21,778)	42,274	(7,758)
Net loss before provision for income taxes	(109,825)	(40,427)	(77,151)
Provision for income taxes	(253)	(269)	(249)
Net loss	$ (110,078)	$ (40,696)	$ (77,400)
Net loss per share-basic and diluted (in dollars per share)	$ (2.82)	$ (1.18)	$ (2.78)
Weighted average shares used in computing basic and diluted net loss per share (in shares)	39,083	34,588	27,883