Stockholders' Equity - Additional Information 2 (Detail) - USD ($)		1 Months Ended			12 Months Ended
	Dec. 31, 2014	Nov. 30, 2014	Sep. 30, 2014	Nov. 30, 2013	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Class Of Stock [Line Items]
Purchase shares of common stock for issued warrants								21,347,182			2,909,750
Cash proceeds from warrant exercises					$ 139,000	$ 55,000	$ 10,874,000
Exercised derivative liabilities					43,796	8,647	1,920,874
Warrants to purchase common stock		145,000		75,000	1,370			650,000
Interest expense					$ 0	$ 1,000	$ 13,000
Warrants maturity term				5 years					5 years	5 years
Volatility		73.40%		96.90%	73.96%	76.90%
Risk-free interest rate		1.21%		0.60%	1.57%	1.60%
Recognized expenses of warrants					$ 0	$ 43,000
Warrants earned, service period				12 months
Warrants issued			50,000
Number of warrant shares vested upon satisfaction of specific performance metrics					95,000
Weighted-average remaining contractual term of options exercisable					6 years 1 month 28 days
Preferred stock, shares authorized					25,000,000
Preferred stock, shares outstanding					0
Consultation Service Agreement September 2014
Class Of Stock [Line Items]
Recognized expenses of warrants	$ 237,000
Consultation Service Agreement November 2014
Class Of Stock [Line Items]
Recognized expenses of warrants					$ 41,000	$ 36,000
Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share					$ 0.85
Warrants maturity term								2 years
Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share					$ 7.62
Warrants maturity term								5 years
Amendment March 2014 [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share							$ 1.00
Warrants to purchase common stock							269,657
Amendment March 2014 [Member] | Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share							$ 0.85
Warrants [Member]
Class Of Stock [Line Items]
Number of warrants exercised					0	203,000	225,000
Cash proceeds from warrant exercises					$ 0	$ 445,000	$ 210,000
Number of warrant exercised through cashless					43,796	8,647	2,628,003
Cashless exercise for issuance of common stock					32,914	7,600	2,139,577
Warrants exercisable price, per share		$ 6.84		$ 7.36
Estimated fair value of warrants		$ 74,000		$ 404,000
Weighted-average remaining contractual term of options exercisable					1 year 3 months 11 days
Warrants [Member] | Consultants [Member]
Class Of Stock [Line Items]
Number of warrants exercised					0	0	348,630
Cash proceeds from warrant exercises							$ 891,000
Warrants [Member] | Minimum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share								$ 1.70
Warrants [Member] | Maximum [Member]
Class Of Stock [Line Items]
Warrants exercisable price, per share								$ 3.24
Warrants [Member] | Amendment March 2014 [Member]
Class Of Stock [Line Items]
Interest expense							$ 12,000