Acquisition and Stockholders' Equity (Deficit) (Details) (USD $)	12 Months Ended			0 Months Ended			2 Months Ended	3 Months Ended	10 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 06, 2012	May 09, 2012	Jun. 21, 2012	Mar. 04, 2014	Dec. 31, 2012	Dec. 31, 2014	Oct. 17, 2012
Acquisition and Stockholders' Equity (Deficit)
Common stock price (in dollars per share)										$ 4.57
Gross proceeds from sale of common stock by the entity (in dollars)	$ 30,700,000	$ 94,734,000	$ 55,862,000
Fees paid related to equity offerings	861,000	5,623,000	3,774,000
Fees and expenses associated with offering	846,000	5,623,000	3,774,000
May 2012 Public Offering
Acquisition and Stockholders' Equity (Deficit)
Common stock issued (in shares)					10,000,000
Common stock price (in dollars per share)					$ 4.50
Gross proceeds from sale of common stock by the entity (in dollars)				51,750,000	45,000,000
Fees paid related to equity offerings				405,000	2,952,930
May 2012 Over-allotment
Acquisition and Stockholders' Equity (Deficit)
Common stock issued (in shares)				1,500,000
Common stock price (in dollars per share)					$ 4.50
Gross proceeds from sale of common stock by the entity (in dollars)				6,750,000
Period during which underwriters could purchase additional shares to cover over-allotments					45 days
June 2012 Amended Controlled Equity Offering Sales Agreement
Acquisition and Stockholders' Equity (Deficit)
Common stock issued (in shares)	6,417,450	758,093					3,644,143	815,654	2,773,507
Gross proceeds from sale of common stock by the entity (in dollars)	30,700,000	4,700,000					21,200,000	4,111,802	9,500,000
Fees paid related to equity offerings		100,000
Maximum share amount to be issued and sold under agreement						30,000,000	30,000,000
Average selling price (in dollars per share)		$ 6.16					$ 5.82	$ 5.04	$ 3.42
Fees and expenses associated with offering								123,385	846,238
Attorney's fee								$ 10,000