Convertible Preferred Stock Warrants - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended	1 Months Ended		6 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Remeasurement [Member]	Mar. 31, 2014 IPO [Member]	Jun. 30, 2014 2010 Notes [Member] Series B convertible preferred stock [Member]	Jun. 30, 2014 2010 Notes [Member] Convertible preferred stock warrants [Member]	Jun. 30, 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