Basis of Presentation - Schedule of Potentially Dilute Earnings Per Share in Future Were Excluded in the Computation of Diluted Net (Loss) Income Per Share as They Were Anti-dilutive (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	15,301,157	13,998,165
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	760,000	760,000
Stock appreciation rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,010,000	690,000
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	834,397	448,709