Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance For Doubtful Accounts Receivable Rollforward
Balance at beginning of year	$ 282	$ 575	$ 294
Provision charged to selling, general and administrative expenses	285	30	301
Allowance resulting from acquisitions	5	52	117
Write-offs, net of recoveries of amounts previously reserved	(29)	(352)	(159)
Divestiture of JK Lasers	(30)
Exchange rate changes	(13)	(23)	22
Balance at end of year	$ 500	$ 282	$ 575