Basic and Diluted Net Loss per Common Share (Details) - shares shares in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded because such instruments were anti-dilutive (in shares)	18,677	544
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded because such instruments were anti-dilutive (in shares)	1,838	498
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded because such instruments were anti-dilutive (in shares)	705	46
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded because such instruments were anti-dilutive (in shares)	14,515	0
Convertible notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded because such instruments were anti-dilutive (in shares)	1,619	0