Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended		1 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014 Vendor	Sep. 30, 2013	Sep. 30, 2013 Supplier concentration risk Inventory	Sep. 30, 2014 Supplier concentration risk Inventory	Sep. 30, 2014 Supplier concentration risk Inventory	Sep. 30, 2014 Supplier concentration risk Accounts payable	Dec. 31, 2013 Supplier concentration risk Accounts payable	Sep. 30, 2013 Warrant	Sep. 30, 2013 Warrant
Summary Of Significant Accounting Policy [Line Items]
Loss on derivative instrument	$ 0	$ 5,931						$ 4,000	$ 5,900
Number of vendors	2
Unrelated vendors, percentage			19.00%	15.00%	18.00%	21.00%	20.00%