Net Loss Per Share -AntiDilutive Common Share Equivalents (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti–dilutive common share equivalents (in shares)	1,711,513	2,278,580
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti–dilutive common share equivalents (in shares)	390,754	530,099
Restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti–dilutive common share equivalents (in shares)	939,809	1,748,481
Restricted stock units (1)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti–dilutive common share equivalents (in shares)	380,950	0