Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net sales	$ 58,652	$ 86,282	$ 134,242
Cost of sales	47,979	76,793	125,922
Gross profit	10,673	9,489	8,320
Research and development expenses	19,658	26,708	38,585
Selling and administrative expenses	13,481	17,094	23,813
Restructuring charges	561	6,098	1,915
	33,700	49,900	64,313
Operating loss	$ (23,027)	(40,411)	(55,993)
Interest income		7	237
Interest expense	$ (83)	(303)	(82)
Other (expense) income, net	(380)	1,817	1,859
Net loss	$ (23,490)	$ (38,890)	$ (53,979)
Basic and diluted loss per share (in dollars per share)	$ (0.27)	$ (0.45)	$ (0.67)
Weighted average basic and diluted common shares outstanding used in computing loss per share (in shares)	88,155	85,810	80,991