Shareholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	9 Months Ended
	Mar. 26, 2014	Sep. 30, 2014	Sep. 30, 2013	Mar. 26, 2014
Temporary Equity [Line Items]
Securities purchase agreements, share	972,004
Price per share of common stock				$ 25.72
Securities purchase agreements gross proceed	$ 25,000	$ 25,000	$ 0
Securities purchase agreements, value		25,000
Affiliates of Third Security
Temporary Equity [Line Items]
Securities purchase agreements, share	243,001
Securities purchase agreements, value	$ 6,250