Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended			0 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Stock Options Granted, Beginning In January 2011	Feb. 28, 2014 Employee Stock Purchase Plan	Mar. 31, 2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation granted under plan vest period			4 years
Term of award			10 years
Percentage of closing price of common stock					85.00%
Common stock purchase				21,774
Proceeds from issuance of common stock				$ 500,000
Stock-based compensation expense	$ 4,342,000	$ 1,671,000