Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year		$ 235	$ 288	$ 115
Additions charged (credited) to costs and expenses		417	(1)	238
Deductions	[1]	(163)	(52)	(65)
Balance at end of year		489	235	288
Inventory Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year		1,823	1,682	181
Additions charged (credited) to costs and expenses		905	369	2,073
Deductions	[1]	(182)	(228)	(572)
Balance at end of year		$ 2,546	$ 1,823	$ 1,682

[1] represents write-offs.