Goodwill and Intangible Assets - Change in the Carrying Value of Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Goodwill [Line Items]
Goodwill, Translation Adjustments		$ (295)	$ (254)	[1]
Goodwill [Roll Forward]
Balance, Beginning Balance		61,369	61,623
Impairment of goodwill		0	0		$ (40,693)
Balance, Ending Balance		$ 61,074	$ 61,369		$ 61,623
Scanners and CAD/CAM Services
Goodwill [Roll Forward]
Impairment of goodwill	$ (40,700)

[1] The adjustments to goodwill were a result of foreign currency translation.