Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions					3 Months Ended		6 Months Ended
	Jun. 17, 2015	Sep. 15, 2014	Sep. 08, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, granted					1,800	23,800	51,800	104,300
Weighted-average grant date fair value					$ 6.85	$ 2.84	$ 6.59	$ 3.23
Unrecognized compensation costs, employee stock options					$ 4.2		$ 4.2
Expected recognition period							1 year 5 months 27 days
Employee Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested				33,333
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested	157,500
Vested options held by 1 employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested		39,167	82,834	71,167
Shares vesting period				9 months
Unvested options held by 1 employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period			3 months
Shares unvested		113,333	23,333	66,667
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period							1 year 11 months 5 days
Unrecognized compensation costs					$ 9.5		$ 9.5
Restricted Stock | Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting period					3 years
Shares issued					1,050,000	0		0