Stock-Based Compensation - Summary of Company's Stock Option Plan Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercised, Number of Options			(30,000)
Granted, Number of Options	110,000
Granted, Weighted Average Exercise Price	$ 40.00
Outstanding, Number of Options	160,000	110,000	130,000	110,000	130,000	110,000	50,000	110,000
Exercisable, Number of Options					20,000	110,000
Exercised, Weighted-Average Exercise Price			$ 2.50
Exercisable, Weighted-Average Exercise Price					$ 6.30	$ 3.19
Outstanding, Weighted-Average Remaining Contractual Term	7 years 4 months 24 days	2 years 1 month 6 days	8 years 8 months 12 days	1 year 9 months 18 days	8 years 6 months	1 year 7 months 6 days	2 years 3 months 19 days	2 years 3 months 19 days
Outstanding, Weighted Average Exercise Price	$ 28.76	$ 3.19	$ 34.82	$ 3.19	$ 34.82	$ 3.19	$ 4.02	$ 3.19
Exercisable, Weighted-Average Remaining Contractual Term					3 years 10 months 25 days	1 year 7 months 6 days
Outstanding, Aggregate Intrinsic Value	$ 2,591	$ 3,312	$ 1,675	$ 2,650	$ 639	$ 2,989	$ 1,773	$ 3,482
Exercisable, Aggregate Intrinsic Value					$ 639	$ 2,989