Stockholders' Equity - Board Compensation (Details) (Common Stock, 2011 Equity Incentive Plan, USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended					12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2014
Common Stock | 2011 Equity Incentive Plan
Stockholders' Equity
Number of days of average trailing stock price used to calculate number of shares of common stock granted	10 days
Issuance of shares to directors for their services	3,731	3,298	3,958	3,473	3,471	14,200
Fair value of shares issued to directors for their services	$ 84	$ 87	$ 88	$ 83	$ 83	$ 341