Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Aug. 31, 2013 Bellevue, WA [Member]
Other Commitments [Line Items]
Expirations of operating leases			2020
Expirations of operating leases						2014-08
Expirations of operating leases						2020-05
Rent expense	$ 402,000	$ 445,000	$ 1,156,000	$ 1,400,000
Restricted cash	$ 250,000		$ 250,000		$ 875,000
Volume pricing agreements period of OVRP			12 months