Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Product revenue	$ 68,349	$ 77,553	$ 76,828
Service revenue	11,966	10,646	9,710
Total revenue	80,315	88,199	86,538
Cost of Revenue:
Cost of product	36,335	38,496	39,705
Cost of services	4,874	4,123	4,232
Total cost of revenue	41,209	42,619	43,937
Gross profit	39,106	45,580	42,601
Operating expenses:
Product development and engineering	20,481	20,448	20,833
Selling, general and administrative	29,674	28,966	35,080
Total operating expenses	50,155	49,414	55,913
Operating loss	(11,049)	(3,834)	(13,312)
Interest expense	0	(55)	(24)
Other income (loss), net	(266)	(48)	671
Loss from continuing operations before provision for income taxes	(11,315)	(3,937)	(12,665)
Provision for income taxes	322	2,871	1,873
Loss from continuing operations	(11,637)	(6,808)	(14,538)
Income (loss) from discontinued operations, net of income taxes of $1,311 and $2,430 in 2015 and 2014, respectively	0	(371)	2,383
Net loss	$ (11,637)	$ (7,179)	$ (12,155)
Net income (loss) per share — basic and diluted
From continuing operations (usd per share)	$ (1.69)	$ (0.97)	$ (1.98)
From discontinued operations (usd per share)	0.00	(0.05)	0.32
Net loss per share — basic and diluted (usd per share)	$ (1.69)	$ (1.02)	$ (1.66)
Weighted average number of shares:
Basic and diluted (shares)	6,886	7,019	7,344