Summary of Financial Information of Laser Quantum - Income Statement (Details) - Laser Quantum - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Financial Statements Information [Line Items]
Revenue	$ 23,526	$ 25,599	$ 23,013
Income from operations	5,537	7,362	7,434
Net income	$ 5,389	$ 6,925	$ 6,627