Net Loss per Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

The following potentially dilutive equity securities were not included in the diluted net loss per common share calculation because they would have had an antidilutive effect:

	As of December 31,
	2016	2015	2014
Stock options	4,123,023	4,871,949	5,112,556
Restricted stock awards and units	352,996	472,384	592,625
Warrants	810,000	869,999	869,999