Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue	$ 81,690	$ 81,102	$ 161,056	$ 149,688
Cost of goods sold	66,015	65,630	129,644	125,034
Gross profit	15,675	15,472	31,412	24,654
Operating expenses:
Research and development	13,793	13,243	28,476	27,131
Sales and marketing	3,623	3,891	8,226	8,015
General and administrative	7,174	7,267	14,927	14,917
Amortization of purchased intangible assets	0	120	119	239
Asset sale related costs	47	79	376	93
Restructuring charges	79	622	258	653
Gain on asset sale	(817)	0	(817)	0
Total operating expenses	23,899	25,222	51,565	51,048
Loss from operations	(8,224)	(9,750)	(20,153)	(26,394)
Interest income	99	122	198	215
Interest expense	(496)	(759)	(989)	(1,467)
Other income (expense), net	1,090	930	(508)	581
Total interest and other income (expense), net	693	293	(1,299)	(671)
Loss before income taxes	(7,531)	(9,457)	(21,452)	(27,065)
Income tax benefit (provision)	205	(1,080)	35	(1,718)
Net loss	$ (7,326)	$ (10,537)	$ (21,417)	$ (28,783)
Basic net loss per share (USD per share)	$ (0.16)	$ (0.24)	$ (0.46)	$ (0.65)
Diluted net loss per share (USD per share)	$ (0.16)	$ (0.24)	$ (0.46)	$ (0.65)
Weighted average shares used to compute basic net loss per share (in shares)	46,754	44,665	46,585	44,463
Weighted average shares used to compute diluted net loss per share (in shares)	46,754	44,665	46,585	44,463