Debt - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended						0 Months Ended	3 Months Ended		6 Months Ended	0 Months Ended		6 Months Ended	0 Months Ended				6 Months Ended	0 Months Ended	6 Months Ended	0 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended		0 Months Ended	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Mar. 02, 2014 Capital Ventures International	Mar. 31, 2014 Capital Ventures International	Sep. 30, 2013 Senior Convertible Debt	Sep. 30, 2013 Senior Convertible Debt	Oct. 09, 2013 Senior Convertible Debt Capital Ventures International	Apr. 04, 2012 Senior Convertible Debt Capital Ventures International	Sep. 30, 2014 Senior Convertible Debt Capital Ventures International	Mar. 02, 2014 New Unsecured Senior Convertible Note	Dec. 31, 2013 New Unsecured Senior Convertible Note	Dec. 31, 2012 New Unsecured Senior Convertible Note	Apr. 04, 2012 New Unsecured Senior Convertible Note	Sep. 30, 2014 New Unsecured Senior Convertible Note Capital Ventures International	Nov. 15, 2013 Senior Secured Loan	Sep. 30, 2014 Senior Secured Loan	Nov. 15, 2013 Senior Secured Loan Hercules Technology Growth Capital	Jun. 05, 2012 Senior Secured Loan Hercules Technology Growth Capital	Dec. 31, 2013 Senior Secured Loan Hercules Technology Growth Capital	Sep. 30, 2013 Senior Secured Loan Hercules Technology Growth Capital	Sep. 30, 2014 Senior Secured Loan Hercules Technology Growth Capital	Sep. 30, 2013 Senior Secured Loan Hercules Technology Growth Capital	Mar. 31, 2013 Senior Secured Loan Hercules Technology Growth Capital	Jun. 30, 2014 Senior Secured Loan Hercules Technology Growth Capital	Jun. 05, 2012 Senior Secured Loan Hercules Technology Growth Capital Minimum	Sep. 30, 2014 Senior Secured Loan Hercules Technology Growth Capital Maximum
Debt Instrument [Line Items]
Net proceeds after fees and expenses of purchase agreement														$ 23,200,000
Conversion price														$ 4.85			$ 3.10	$ 3.19	$ 4.85
Premium over closing price, percentage														20.00%
Period before first installment payment														4 months
Shares registered for resale														10,262,311
Derivative liability of note	1,841,000		1,841,000		2,601,000									3,800,000						500,000
Number of shares received from warrants received to purchase common stock														3,094,060							256,410		256,410	139,276
Strike price per share													$ 2.61	$ 5.45	$ 2.55						$ 1.95	$ 1.94	$ 1.95	$ 3.59	$ 1.95		$ 1.94
Fair value of warrants at issuance														7,000,000										400,000
Increase in derivative liability																				1,500,000
Total debt discount being amortized into interest expense																				13,100,000							200,000			100,000
Non-cash interest expense amortization of debt discount	200,000	3,100,000	300,000	4,800,000							1,200,000	2,700,000														100,000	100,000	300,000				100,000
Percentage of stock discount			85.00%
Number of trading days for valuation of shares			10 days
Non-cash interest expense issuing stock at discount	1,800,000			1,800,000
Debt conversion, shares issued									6,600,000							6,600,000
Loss on extinguishment of debt										(5,200,000)
Legal and origination costs	10,188,000		10,188,000																						200,000				300,000
Debt, face amount																							10,000,000	10,000,000
Net proceeds from debt																							9,800,000	9,700,000
Interest rate on loan																								11.00%
Prime rate																															3.75%
End of term fee																											500,000		500,000
Interest expense	500,000	3,500,000	1,000,000	5,600,000																							1,000,000		1,200,000
Minimum amount of proceeds from specified asset dispositions for mandatory prepayment feature																											1,000,000
Covenant, unrestricted cash balance requirement																							15,000,000				9,800,000
Net proceeds from sale of common stock																											5,000,000
Repayments of term loan																											2,500,000
Combined principal balances of the term loans		$ 10,411,000		$ 10,411,000		$ 10,411,000	$ 14,389,000	$ 15,380,000																			$ 7,500,000