Intangible Assets - Additional Information (Detail) - Intellectual Property Rights [Member] - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite Lived Intangible Assets [Line Items]
Estimated useful life	10 years
Amortization expenses	$ 100,000	$ 100,000	$ 40,000
Remaining amortization period	7 years 3 months 18 days	8 years 3 months 18 days
Impairment charges	$ 0	$ 0	$ 0