Net Income (Loss) Per Share - Narrative (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of weighted-average shares outstanding, includes potentially dilutive securities or unvested restricted stock (in shares)			0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of weighted-average shares outstanding, includes potentially dilutive securities or unvested restricted stock (in shares)	0	672,000	0	672,000
Vested and remaining outstanding (in shares)	988,000		988,000