Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 79,366	$ 68,586
Cost of goods sold	63,629	59,404
Gross profit	15,737	9,182
Operating expenses:
Research and development	14,683	13,888
Sales and marketing	4,603	4,124
General and administrative	7,753	7,650
Amortization of purchased intangible assets	119	119
Asset sale related costs	329	14
Restructuring charges	179	31
Total operating expenses	27,666	25,826
Loss from operations	(11,929)	(16,644)
Interest income	99	93
Interest expense	(493)	(708)
Other income (expense), net	(1,598)	(349)
Total interest and other income (expense), net	(1,992)	(964)
Loss before income taxes	(13,921)	(17,608)
Provision for income taxes	(170)	(638)
Net loss	$ (14,091)	$ (18,246)
Basic net loss per share (USD per share)	$ (0.30)	$ (0.41)
Diluted net loss per share (USD per share)	$ (0.30)	$ (0.41)
Weighted average shares used to compute basic net loss per share (in shares)	46,414	44,259
Weighted average shares used to compute diluted net loss per share (in shares)	46,414	44,259