Goodwill and Intangible Assets Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Dispose, impair or recognition of additional goodwill	$ 0
Impairment charges on goodwill	0
Impairment losses recognized related to the acquired intangible assets	0	$ 0	$ 0
Annual amortization expense of the intangible assets, 2017	200,000
Annual amortization expense of the intangible assets, 2018	200,000
Annual amortization expense of the intangible assets, 2019	200,000
Annual amortization expense of the intangible assets, 2020	$ 100,000