Warrants and Derivative Liabilities - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended			9 Months Ended		0 Months Ended		3 Months Ended	9 Months Ended			9 Months Ended	1 Months Ended		0 Months Ended	3 Months Ended	0 Months Ended		3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Convertible Bond	Dec. 31, 2012 Convertible Bond	Dec. 31, 2013 Convertible Bond	Dec. 31, 2012 Convertible Bond	Dec. 31, 2012 Warrants And Derivative Liability	Dec. 31, 2012 Warrants And Derivative Liability	Dec. 31, 2013 Maximum Senior Secured Term Loan – Second Warrant	Dec. 31, 2013 Maximum Senior Secured Term Loan – Second Warrant	Dec. 31, 2013 Capital Ventures International	Sep. 30, 2013 Capital Ventures International	Dec. 31, 2012 Capital Ventures International	Dec. 31, 2013 Capital Ventures International	Dec. 31, 2012 Capital Ventures International	Oct. 09, 2013 Senior Convertible Debt Capital Ventures International	Apr. 04, 2012 Senior Convertible Debt Capital Ventures International	Dec. 31, 2013 Senior Convertible Debt Capital Ventures International	Dec. 31, 2013 New Unsecured Senior Convertible Note	Dec. 31, 2012 New Unsecured Senior Convertible Note	Apr. 04, 2012 New Unsecured Senior Convertible Note	Dec. 31, 2013 New Unsecured Senior Convertible Note Capital Ventures International	Dec. 31, 2012 New Unsecured Senior Convertible Note Capital Ventures International Minimum	Dec. 31, 2012 New Unsecured Senior Convertible Note Capital Ventures International Maximum	Nov. 15, 2013 Senior Secured Term Loan	Dec. 31, 2013 Senior Secured Term Loan Maximum	Nov. 15, 2013 Senior Secured Term Loan Hercules Technology Growth Capital	Jun. 05, 2012 Senior Secured Term Loan Hercules Technology Growth Capital	Dec. 31, 2013 Senior Secured Term Loan Hercules Technology Growth Capital
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock																			3,094,060								256,410		256,410	139,276
Warrant exercise, waiting period																6 months
Warrant exercise period																5 years
Exercise price																		$ 2.61	$ 5.45	$ 2.59							$ 1.95		$ 1.95	$ 3.59	$ 1.95
Beneficial ownership limitation percentage																									4.99%	9.99%
Required notification period																61 days
Gain (loss) in change of fair value of derivative instruments and warrants	$ 535,000	$ 5,217,000	$ 1,890,000	$ 6,114,000	$ 200,000	$ 2,300,000	$ 500,000	$ 3,300,000	$ 200,000	$ 200,000	$ 100,000	$ 100,000	$ (1,000,000)	$ 300,000	$ 2,700,000	$ 1,200,000	$ (2,600,000)											$ 100,000
Conversion price																			$ 4.85		$ 3.15	$ 4.85	$ 3.19		$ 3.19	$ 4.85
Increase in derivative liability																					$ 500,000			$ 500,000
Convertible debt instrument redemption waiting period			1 year
Convertible debt instrument contractual term			30 months