Convertible Preferred Stock Warrants - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended	1 Months Ended		3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Remeasurement [Member]	Mar. 31, 2014 IPO [Member]	Mar. 31, 2014 2010 Notes [Member] Convertible preferred stock warrants [Member]	Mar. 31, 2014 2010 Notes [Member] Series B convertible preferred stock [Member]	Mar. 31, 2014 2012 Notes [Member]	Dec. 31, 2013 2012 Notes [Member]
Class of Stock [Line Items]
Percentage of shares issuable on conversion of debt as warrants					20.00%		20.00%
Fair value of warrants					$ 233,000		$ 433,000	$ 474,000
Expected term (in years)		1 year 1 month 6 days			1 year 9 months		1 year 6 months
Expected volatility		75.00%			85.00%		90.00%
Risk-free interest rate		0.13%			0.53%		0.21%
Exercise price per share of warrant exercised						900,000
Number of securities issued upon exercise of warrants	158,179					2,000,000
Warrants expiration date							Oct. 12, 2017
Warrants term							5 years
Remeasurement of outstanding warrants	173,910
Warrants remeasured using intrinsic value of warrant computed as difference between IPO price and exercise price	5.17			21.00
Expense related to change in fair value			2,300,000
Reclassified to additional paid in capital			$ 2,800,000