Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Accounting Policies [Abstract]
Unrealized gain (loss) on available-for-sale investments	$ 58,000	$ 17,000	$ 169,000	$ 66,000
Realized investment gains or losses	0	$ 0	0	$ 0
Investments owned, at fair value			0
Long-term debt, fair value	$ 124,200,000		$ 124,200,000		$ 140,100,000
Warrants exercise price	$ 0.05		$ 0.05