Subsequent Event - Additional Information (Detail)	9 Months Ended		9 Months Ended	1 Months Ended
	Sep. 30, 2013 Fourth amendment to lease agreement [Member] Y sqft	Jun. 30, 2013 Fourth amendment to lease agreement [Member] sqft	Sep. 30, 2013 Fourth amendment to lease agreement [Member] Maximum [Member] Y	Oct. 31, 2013 Subsequent Event [Member] Lease agreement [Member] sqft
Subsequent Event [Line Items]
Operating lease space, in square feet	98,000	13,000		44,000
Lease expiry period	June 2019			July 2024
Optional lease extension term, in years	5		5