Subsequent Events - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			1 Months Ended
	Jun. 25, 2013	Dec. 31, 2013	Apr. 30, 2013 Term Loan Facility [Member]	Dec. 31, 2012 Term Loan Facility [Member]	Feb. 28, 2014 Subsequent Event [Member]	Jan. 31, 2014 Subsequent Event [Member]	Jan. 31, 2014 Subsequent Event [Member] Term Loan Facility [Member]	Jan. 31, 2014 Subsequent Event [Member] Term Loan Facility [Member] Option 1 [Member]
Subsequent Event [Line Items]
Underwritten public offering, shares sold	5,400,000					2,972,972
Proceeds from underwritten public offering		$ 46,820,000				$ 55,000,000
Underwriters partially exercised an overallotment option, shares					345,945
Underwriters partially exercised an overallotment option, additional gross proceeds					6,400,000
Proceeds from underwritten public offering after commissions					57,000,000
Credit facility, additional borrowing capacity			$ 5,000,000	$ 13,000,000			$ 45,000,000	$ 52,000,000