Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Net (Loss) Income per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Basic and diluted net loss per share:
Net income (loss)	$ 1,330	$ (1,360)	$ 2,334	$ (7,167)
Weighted average common shares outstanding		24,262,417		24,485,429
Basic and diluted net loss per share		$ (0.06)		$ (0.29)
Basic:
Net income	1,330	(1,360)	2,334	(7,167)
Weighted average common shares outstanding, basic	24,425,081	24,262,417	24,134,686	24,485,429
Net income per share, basic	$ 0.05	$ (0.06)	$ 0.10	$ (0.29)
Diluted:
Net income	$ 1,330	$ (1,360)	$ 2,334	$ (7,167)
Weighted average common shares outstanding	24,425,081	24,262,417	24,134,686	24,485,429
Add: Options to purchase common shares and restricted stock units	734,259		755,044
Weighted average common shares outstanding, diluted	25,159,340	24,262,417	24,889,730	24,485,429
Net income per share, diluted	$ 0.05	$ (0.06)	$ 0.09	$ (0.29)