Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Accounting Policies [Abstract]
Impairment of investments		$ 0
Based on these sales prices reduced inventory and increased cost of goods sold	107,000	421,000
Reduced inventory and increased costs of goods sold	46,000	255,000
Revenue recorded from government contract	110,000	208,000
Period of contract	3 years
Total value of the contract	4,700,000	4,700,000
Value of contract recorded	$ 1,400,000