Share Based Payments - Schedule of Fair Value of Non-Employee Stock Options Granted Estimated Using Black-Scholes Option Pricing Model With Following Weighted Average Assumptions (Details) - Non-employee Stock Options - $ / shares	9 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock price	$ 9.60	$ 12.15
Exercise price	$ 6.75	$ 12.20
Expected term	3 years 9 months	10 years
Expected volatility	84.16%	91.02%
Risk-free interest rate	0.98%	1.60%
Dividend rate	0.00%	0.00%