Goodwill and Intangible Assets - Schedule of Goodwill (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Balance at December 31, 2016	[1]			$ 19,318,000
Impairment		$ 0	$ 0	(2,797,000)	$ 0
Foreign currency translation adjustments				220,000
Balance at September 30, 2017		$ 16,741,000		$ 16,741,000

[1] Derived from our audited consolidated financial statements as of December 31, 2016.