Basic and Diluted Net Loss per Common Share - Anti-Dilutive Securities Excluded from Computation (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents outstanding (in shares)	18,878	654	431
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents outstanding (in shares)	1,715	86	418
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents outstanding (in shares)	1,029	0	13
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents outstanding (in shares)	14,515	568	0
Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents outstanding (in shares)	1,619	0	0