CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenue, net	$ 56,112	$ 43,968	$ 43,259
Cost of revenue	28,637	22,618	24,775
Gross profit	27,475	21,350	18,484
Operating expenses:
Research and development	14,094	15,896	12,795
Sales and marketing	11,064	11,026	8,345
General and administrative	7,148	6,693	3,978
Gain from settlement with former foundry supplier		(1,962)
Total operating expenses	32,306	31,653	25,118
Loss from operations	(4,831)	(10,303)	(6,634)
Other (expense):
Interest expense, net	(753)	(1,275)	(1,115)
Other (expense), net	(3)	(50)	(695)
Total other (expense), net	(756)	(1,325)	(1,810)
Loss before provision for (benefit from ) income taxes	(5,587)	(11,628)	(8,444)
Provision for (benefit from) income taxes	101	(16)	(61)
Net loss	$ (5,688)	$ (11,612)	$ (8,383)
Net loss per share:
Basic and diluted	$ (0.31)	$ (0.77)	$ (2.79)
Weighted average number of shares used in computing net loss per share:
Basic and diluted	18,591,308	15,085,973	3,007,929