Borrowings - Loan Agreement - Additional Information (Detail) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
	Feb. 25, 2015	Nov. 06, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Nov. 30, 2012
Schedule Of Debt Instruments [Line Items]
Extension period for interest-only payment		4 months
Interest expense			$ 4,482	$ 4,570	$ 9,048	$ 9,081
Loan and Security Agreement [Member]
Schedule Of Debt Instruments [Line Items]
Discount on loan recorded as a non-current liability to be paid upon full repayment or maturity of the loans			1,200		1,200
Interest expense			1,200	$ 1,200	2,300	$ 2,400
Hercules [Member]
Schedule Of Debt Instruments [Line Items]
Less unamortized discount			$ 1,600		$ 1,600
Hercules [Member] | Loan and Security Agreement [Member]
Schedule Of Debt Instruments [Line Items]
Aggregate principal amount of loans received	$ 40,000						$ 40,000
Outstanding principal balance repayment period	Jun. 01, 2016
Outstanding principal balance repayment period	Nov. 01, 2018
Extended maturity period on principal payment	6 months
Additional term loan advance by company	$ 15,000