Public Offerings of Common Stock (Tables)

3 Months Ended

Mar. 31, 2016

Text Block [Abstract]

Schedule of Total Sales under 2015 and 2016 Sales Agreement

The following table summarizes the total sales under the 2015 Sales Agreement and 2016 Sales Agreement for the periods indicated (in thousands, except per share amounts):

	2015 Sales				2016 Sales
	Agreement				Agreement
	Three Months Ended		Year Ended		Three Months Ended
	March 31, 2016		December 31, 2015		March 31, 2016
Total shares of common stock sold		5,710.2		2,014.3		3,427.5
Average price per share	$	3.23	$	3.25	$	4.11
Gross proceeds	$	18,454	$	6,546	$	14,084
Commissions earned by Cantor	$	553	$	197	$	423
Other issuance costs	$	0	$	259	$	165