Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2014 Vendor	Jun. 30, 2013	Jun. 30, 2014 Supplier concentration risk Inventory	Jun. 30, 2014 Supplier concentration risk Inventory	Jun. 30, 2014 Supplier concentration risk Accounts payable	Jun. 30, 2013 Warrant	Jun. 30, 2013 Warrant
Summary Of Significant Accounting Policy [Line Items]
Loss on derivative instrument	$ 0	$ 1,975,000				$ 2,323,000	$ 2,000,000
Number of vendors	2
Unrelated vendors, percentage			19.00%	18.00%	22.00%