Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue:
Revenue	$ 27,688	$ 23,085
Total revenue	27,688	23,085
Costs and expenses:
Cost of product and service revenue	8,709	7,695
Research and development	16,027	13,832
Selling, general and administrative	23,436	19,437
Total costs and expenses	48,172	40,964
Loss from operations	(20,484)	(17,879)
Other income (expense):
Interest income	523	238
Interest expense	(1,748)	(1,563)
Other income (expense), net	(110)	65
Total other income (expense), net	(1,335)	(1,260)
Net loss before provision for income tax	(21,819)	(19,139)
Provision for income tax	(79)	(63)
Net loss	$ (21,898)	$ (19,202)
Net loss per share - basic and diluted (in dollars per share)	$ (0.69)	$ (0.75)
Weighted average shares used in computing basic and diluted net loss per share (in shares)	31,569	25,479
Total product and service revenue
Revenue:
Revenue	$ 21,350	$ 18,045
Collaboration revenue
Revenue:
Revenue	$ 6,338	$ 5,040