Commitments And Contingencies - Additional Information (Detail) (USD $)	1 Months Ended		12 Months Ended			1 Months Ended
	Jan. 31, 2011	Jan. 31, 2008	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jan. 31, 2009 Third party one	Mar. 31, 2012 Third party two
Loss Contingencies [Line Items]
Noncancelable operating lease, commenced period	2011-07	2008-02
Noncancelable operating lease, expiration period	2014-06	2011-06				2011-06	2014-06
Standby letters of credit issued under lease term			$ 205,000	$ 205,000
Deferred rent				200,000
Sublease agreement, term						29 months	28 months
Sublease agreement, start date						2009-02-01	2012-03-01
Rent expense, net of sublease income			100,000	600,000	400,000
Sublease income			1,000,000	500,000	400,000
Accruals or expenses related to indemnification issues			$ 0