Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended		9 Months Ended								9 Months Ended		12 Months Ended	9 Months Ended
	Sep. 30, 2014 Customer	Sep. 30, 2013	Sep. 30, 2014 Segment Customer	Sep. 30, 2013	Dec. 31, 2013 Customer		Sep. 30, 2014 2009 Unit Offering	Aug. 31, 2009 2009 Unit Offering	Sep. 30, 2014 2010 Unit Offering	Nov. 30, 2010 2010 Unit Offering	Sep. 30, 2014 Computer Software, Intangible Asset	Sep. 30, 2014 Trade Accounts Receivable	Dec. 31, 2013 Trade Accounts Receivable	Sep. 30, 2014 Minimum	Sep. 30, 2014 Maximum
Summary Of Significant Accounting Policies [Line Items]
Number of major customers representing outstanding trade receivables	4		4		2
Cumulative outstanding trade receivables percentage by major customers												77.00%	55.00%
Life of inventory			2 years
Protracted length of inventory			1 year
Inventory valuation reserves	$ 100,000		$ 100,000		$ 400,000
Estimated useful life of property and equipment														3 years	5 years
Capitalized costs for enhancement of enterprise resource planning software system and other internal use software	1,800,000	0	1,800,000	0
Enterprise resource planning system, estimated useful life											5 years
Estimated useful life of intangible assets			10 years
Number of operating segments			1
Number of reportable segments			1
Impairment charges on long-lived assets	0	0	0	0
Warrants to purchase an aggregate shares of common stock								2.4		3.7
Warrant liability	$ 3,931,000		$ 3,931,000		$ 20,390,000	[1]	$ 0		$ 3,300,000
Company's tax years subject to examination by the taxing jurisdictions														1998	2013
Period of warranty			1 year

[1] The financial information in this column was derived from audited financial statements included in the Company's 2013 Annual Report on Form 10-K.