Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenue	$ 322,540	$ 292,894	$ 411,423
Cost of goods sold	256,367	231,415	294,290
Gross profit	66,173	61,479	117,133
Operating expenses:
Research and development	53,818	58,287	57,376
Sales and marketing	16,728	17,760	18,595
General and administrative	30,403	34,453	34,409
Amortization of purchased intangible assets	475	472	1,609
Acquisition and asset sale related costs	427	130	2,125
Restructuring charges	3,135	3,934	0
Litigation settlement	2,645	0	0
Loss (gain) on asset sale	200	(2,193)	0
Total operating expenses	107,831	112,843	114,114
Income (loss) from operations	(41,658)	(51,364)	3,019
Interest income	397	198	303
Interest expense	(2,493)	(1,362)	(402)
Other income, net	1,446	104	472
Total interest and other income (expense), net	(650)	(1,060)	373
Income (loss) before income taxes	(42,308)	(52,424)	3,392
Provision for income taxes	(1,329)	(909)	(3,597)
Net loss	$ (43,637)	$ (53,333)	$ (205)
Basic net loss per share (USD per share)	$ (0.97)	$ (1.23)	$ 0.00
Diluted net loss per share (USD per share)	$ (0.97)	$ (1.23)	$ 0.00
Weighted average shares used to compute basic net loss per share (in shares)	45,144	43,431	41,798
Weighted average shares used to compute diluted net loss per share (in shares)	45,144	43,431	41,798