Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accounting Policies [Abstract]
Impairment of investments			$ 0
Based on these sales prices reduced inventory and increased cost of goods sold	$ 815,000.0	$ 354,000.0	1,100,000	$ 1,500,000
Reduced inventory and increased costs of goods sold		363,000		363,000
Impairment losses on long lived assets			0
Revenue recorded from government contract	144,000	$ 272,000	286,000	$ 397,000
Total value of the contract	$ 4,700,000		4,700,000
Value of contract recorded			$ 3,600,000