Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Accounting Policies [Abstract]
Impairment of investments			$ 0
Based on these sales prices reduced inventory and increased cost of goods sold	276,000.0		1,800,000		421,000.0
Reduced inventory and increased costs of goods sold	1,800,000		2,200,000		604,000.0
Impairment of property plant and equipment			0
Revenue recorded from government contract	156,000.0	882,000.0	553,000.0	1,100,000
Period of contract			3 years
Total value of the contract	4,700,000		4,700,000
Value of contract recognized			$ 3,300,000