Stockholders' Equity (Details) (USD $)	12 Months Ended		48 Months Ended	12 Months Ended	1 Months Ended			0 Months Ended	1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2008	Dec. 31, 2014	Nov. 30, 2013	May 31, 2014	Sep. 30, 2012	Dec. 28, 2012	Oct. 31, 2012
Convertible Preferred Stock and Stockholders' Equity
Common stock, shares authorized	150,000,000	147,000,000		1,000,000,000	150,000,000
Cash paid for repurchase of common stock	$ 1,000,000	$ 1,648,000
Aggregate amount of shares repurchased		1,648,000
Preferred Stock Warrants converted to common stock warrants
Convertible Preferred Stock and Stockholders' Equity
Number of shares that may be purchased under warrant			412,222	0
Reclassification of warrant liability to APIC			2,600,000
Preferred Stock Warrants converted to common stock warrants | Exercise price of $1.53 per share
Convertible Preferred Stock and Stockholders' Equity
Number of shares that may be purchased under warrant	32,222
Exercise price of warrants (in dollars per share)	$ 1.53		$ 1.53	$ 1.53
Shares issued for exercise of warrants	21,093			28,555
Number of shares exercised through a net settlement				32,222
Preferred Stock Warrants converted to common stock warrants | Exercise price of $1.80 per share
Convertible Preferred Stock and Stockholders' Equity
Exercise price of warrants (in dollars per share)		$ 1.80	$ 1.80
Shares issued for exercise of warrants		353,856
Vulcan
Convertible Preferred Stock and Stockholders' Equity
Aggregate purchase price for preferred stock and warrants					30,000,000
Vulcan | Common Stock Purchase Warrants
Convertible Preferred Stock and Stockholders' Equity
Number of shares that may be purchased under warrant					666,666
Exercise price of warrants (in dollars per share)					$ 15.00
Aggregate purchase price for preferred stock and warrants					700,000
Common stock
Convertible Preferred Stock and Stockholders' Equity
Shares sold				8,941,250
Shares of common stock issued for conversion of Series A						2,857,143
Shares repurchased		265,274
Repurchase price (in dollars per share)		$ 6.21
Cash paid for repurchase of common stock		1,700,000
Shares issued for exercise of warrants		377,672		3,357,867
Common stock | CEO
Convertible Preferred Stock and Stockholders' Equity
Shares repurchased							110,278
Common stock | CEO | Employment agreement
Convertible Preferred Stock and Stockholders' Equity
Shares repurchased	112,422	130,080						130,080
Repurchase price (in dollars per share)	$ 8.90							$ 8.00
Cash paid for repurchase of common stock	1,000,000
Share value for which right to sell is provided	1,000,000	1,000,000
Vesting term of shares for which right to sell to the Company is provided	6 months	6 months
Common stock | Former employee | Severance agreement
Convertible Preferred Stock and Stockholders' Equity
Shares repurchased									24,916
APIC
Convertible Preferred Stock and Stockholders' Equity
Aggregate amount of shares repurchased		1,648,000
Series A preferred stock
Convertible Preferred Stock and Stockholders' Equity
Shares authorized	4,500,000			0	4,500,000
Series A preferred stock | Vulcan
Convertible Preferred Stock and Stockholders' Equity
Shares sold					2,857,143
Private placement price per share (in dollars per share)					$ 10.50
Aggregate purchase price for preferred stock and warrants					$ 29,200,000
Conversion ratio						1