Summary of Significant Accounting Policies - Product Warranty Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Balance, beginning of period	$ 97	$ 141
Charged to cost of sales	90	407
Actual product warranty expenditures	(114)	(451)
Balance, end of period	$ 73	$ 97