Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2013 Customer	Sep. 30, 2012	Sep. 30, 2013 Customer	Sep. 30, 2012	Dec. 31, 2012 Customer	Sep. 30, 2013 Product Warranty	Dec. 31, 2012 Product Warranty	Aug. 31, 2009 2009 Unit Offering Warrant	Nov. 30, 2010 2010 Unit Offering Warrant	Sep. 30, 2013 Maximum	Sep. 30, 2013 Minimum	Dec. 31, 2012 Minimum
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue	$ 111,000		$ 111,000		$ 77,000
Number of major customers representing outstanding trade receivables	3		3		3
Cumulative outstanding trade receivables percentage by major customers			55.00%		59.00%						10.00%	10.00%
Life of inventory			2 years
Protracted length of inventory			1 year
Estimated useful life of property and equipment										5 years	3 years
Estimated useful life of intangible assets			10 years
Impairment charges on long-lived assets	0	0	0	0
Foreign currency gains (losses)	409,000	187,000	198,000	(53,000)
Warrants to purchase an aggregate shares of common stock								2.4	3.7
Company's tax years subject to examination by the taxing jurisdictions										2012	1998
Unrecognized Tax Benefits	0		0		0
Warranty claim	394,000		394,000		2,038,000	0	1,800,000
Inventory write down					$ 1,700,000
Period of warranty			1 year