Reduction in Worforce (Details) - USD ($)		6 Months Ended	12 Months Ended
	Sep. 20, 2016	Jun. 30, 2016	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring costs		$ 600,000
Restructuring charges	$ 1,300,000		$ 1,940
Restructuring Reserve [Roll Forward]
Beginning Balance		$ 0	0
Charges	$ 1,300,000		1,940
Payments			(1,909)
Ending Balance			31
General and administrative expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges			800,000
Restructuring Reserve [Roll Forward]
Charges			800,000
Research and development expense
Restructuring Cost and Reserve [Line Items]
Restructuring charges			1,100,000
Restructuring Reserve [Roll Forward]
Charges			$ 1,100,000