CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 30,432	$ 25,164	$ 58,790	$ 48,807
Cost of revenue	12,914	10,912	25,155	20,959
Gross profit	17,518	14,252	33,635	27,848
Operating expenses:
Research and development	12,772	10,537	25,346	20,944
Sales and marketing	2,614	1,822	4,901	3,456
General and administrative	3,324	2,248	6,321	4,475
Total operating expenses	18,710	14,607	36,568	28,875
Loss from operations	(1,192)	(355)	(2,933)	(1,027)
Other income (expense):
Interest expense		(457)		(1,016)
Change in fair value of convertible preferred stock warrant liability		(1,040)		(1,700)
Other income, net	291	11	539	28
Total other income (expense)	291	(1,486)	539	(2,688)
Loss before income tax expense	(901)	(1,841)	(2,394)	(3,715)
Provision for (benefit from) income taxes	(68)	(509)	(193)	(358)
Net loss	$ (833)	$ (1,332)	$ (2,201)	$ (3,357)
Net loss per share, basic and diluted	$ (0.02)	$ (0.29)	$ (0.07)	$ (0.74)
Weighted-average shares used to compute net loss per share, basic and diluted	33,836	4,621	33,666	4,549
Comprehensive income:
Net loss	$ (833)	$ (1,332)	$ (2,201)	$ (3,357)
Other comprehensive income (loss), net of tax:
Unrealized gains and losses - short-term investments	52		(79)
Comprehensive loss	$ (781)	$ (1,332)	$ (2,280)	$ (3,357)