Stock-Based Compensation - Stock Options - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Mar. 31, 2015	Jul. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range of exercise prices					$ 5.50
Upper range of exercise prices					11.00
Intrinsic value based on share price			$ 6.01		$ 6.01
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock options vesting provisions, description					Employee options contain installment vesting typically over a period of four years.
Options vested in remaining period					4 years
Period of termination of employment					90 days
Stock options granted period		10 years			7 years
Stock options awarded	130,000		1,500		20,500
Options exercised			0	1,894	35,134	41,841
Proceeds from options exercised				$ 13	$ 300	$ 300
Intrinsic value				$ 2	$ 34	$ 55
Lower range of exercise prices					$ 5.50
Upper range of exercise prices					$ 11.00
Period of expected life, options granted					5 years
Weighted average period					1 year 2 months 12 days
Unrecognized compensation expense			$ 400		$ 400