Public Offerings of Common Stock (Tables)

6 Months Ended

Jun. 30, 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 Agreement				2016 Sales Agreement
	Six Months Ended June 30, 2016		Year Ended December 31, 2015		Six Months Ended June 30, 2016
Total shares of common stock sold		5,710.2		2,014.3		8,763.4
Average price per share	$	3.23	$	3.25	$	4.70
Gross proceeds	$	18,454	$	6,546	$	41,156
Commissions earned by Cantor	$	553	$	197	$	1,235
Other issuance costs	$	—	$	259	$	185