Stock-Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Number of Shares, Outstanding Beginning Balance	2,732,221	1,663,221
Number of shares granted	1,835,600	1,089,000
Number of Shares, Exercised	(2,500)	(2,800)
Number of Shares, Cancelled	(25,000)	(17,200)
Number of Shares, Outstanding Ending Balance	4,540,321	2,732,221	1,663,221
Number of Shares, Exercisable	1,422,014
Weighted Average Exercise Price, Outstanding Beginning Balance	$ 4.07	$ 2.86
Weighted Average Exercise Price, Granted	11.33	5.89
Weighted Average Exercise Price, Exercised	5.00	2.86
Weighted Average Exercise Price, Cancelled	7.79	2.86
Weighted Average Exercise Price, Outstanding Ending Balance	7.08	$ 4.07	$ 2.86
Weighed Average Exercise Price, Exercisable	$ 4.81
Weighted Average Remaining Contractual Life (in Years)	5 years 1 month 28 days	5 years 9 months 3 days	6 years 2 months 19 days
Weighted Average Remaining Contractual Life (in Years), Exercisable	4 years 8 months 4 days