Share-based Compensation - Stock Option Activity (Details)	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Unvested, beginning balance (in shares) | shares	177,260
Granted (in shares) | shares	244,785
Vested (in shares) | shares	(44,312)
Forfeited (in shares) | shares	(18,474)
Unvested, ending balance (in shares) | shares	359,259
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 6.09
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	4.41
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	6.09
Forfeited, weighted average grant date fair value (in dollars per share) | $ / shares	6.09
Unvested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 4.95