Share Based Payments - Additional Information (Detail)	6 Months Ended	1 Months Ended
	Jun. 30, 2013 Employee Stock Purchase Plan [Member]	Jun. 30, 2013 2005 Stock Option Plan [Member]	Jun. 06, 2013 2005 Stock Option Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Additional number of shares of common stock available for issuance		1,500,000
Maximum number of shares authorized under the plan			4,900,000
Shares subject to outstanding awards under the plan		2,600,000
Shares available for grant under the plan		1,200,000
Common stock at a discount	15.00%
Share based compensation arrangement by share based payment award options period description	Option periods under the ESPP run from January 1 to June 30 and July 1 to December 31 of each year. The first purchase occurred on June 30, 2013, and 5.3 shares were issued with the purchase.
Share based compensation arrangement by share based payment award shares issued	5.3