Significant Accounting Policies - At The Market Program (USD $)	12 Months Ended	1 Months Ended	3 Months Ended
	Dec. 31, 2014	Apr. 30, 2015	Mar. 31, 2015
June 2014 Equity Distribution Agreement [Member]
Stock Issued Under At the Market Program	2,528,416
Net Proceeds Received From Share Issuances Under At The Market Program	$ 34,200,000
Total value of Common Stock to be issued under Equity Distribution Agreement	35,000,000
Equity Distribution Agreement Date	June 17, 2014
September 2014 Equity Dsitribution Agreement [Member]
Stock Issued Under At the Market Program	5,087,646
Net Proceeds Received From Share Issuances Under At The Market Program	69,100,000
Total value of Common Stock to be issued under Equity Distribution Agreement	75,000,000
Equity Distribution Agreement Date	September 3, 2014
March 2015 Equity Distribution Agreement [Member]
Stock Issued Under At the Market Program		393,892	1,196,572
Net Proceeds Received From Share Issuances Under At The Market Program		5,100,000	16,000,000
Total value of Common Stock to be issued under Equity Distribution Agreement			$ 100,000,000
Equity Distribution Agreement Date			March 2, 2015