Organization and Operations - Registered Direct Offering (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2016	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Common stock offering
Aggregate gross proceeds from the offering			$ 11,994	$ 61,744
Proceeds from registered direct offering, net of issuance costs			10,603
Accumulated deficit			$ (144,070)	$ (108,010)
Over-Allotment option for underwriters
Common stock offering
Number of shares issued		750,000
Common Stock
Common stock offering
Number of shares issued			3,243,015	5,750,000
Aggregate gross proceeds from the offering			$ 3	$ 5
Common Stock | Registered Direct Offering
Common stock offering
Number of shares issued	2,875,000
Share price (in dollars per share)	$ 4.00
Aggregate gross proceeds from the offering	$ 11,500
Proceeds from registered direct offering, net of issuance costs	$ 10,600
Common Stock | Over-Allotment option for underwriters
Common stock offering
Number of shares issued	375,000