Related Party Transactions - Additional Information (Detail) (USD $)	6 Months Ended	12 Months Ended	1 Months Ended	3 Months Ended	6 Months Ended		6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Aug. 31, 2012 Peregrine [Member]	Jun. 30, 2013 Peregrine [Member]	Jun. 30, 2013 Peregrine [Member]	Dec. 31, 2012 Peregrine [Member]	Jun. 30, 2013 Series D1 Preferred Shares [Member]	Nov. 30, 2008 Series D1 Preferred Shares [Member] Peregrine [Member]	Aug. 08, 2012 Common stock [Member] Peregrine [Member]
Related Party Transaction Due From To Related Party [Line Items]
Purchase of preferred shares								1,345,444
Value of preferred shares								$ 2,000,000
Outstanding shares, description							Less than 1%
Outstanding shares, percentage					1.00%
Description of conversion of preferred shares to common			conversion of the preferred shares to common stock at a ratio of 7.34:1, or 183,303 shares of common stock
Conversion of preferred stock to common stock ratio			7.341
Conversion of preferred stock to common stock shares									183,303
Lock out period until which Company could not sell shares					2013-02
Unrealized gain (loss) on investments	(483,000)	457,000		209,000	(806,000)
Revenue from related party				3,200,000	8,600,000
Accounts receivable from related party				$ 1,600,000	$ 1,600,000	$ 1,700,000