Share-based Compensation - Summary of Stock Option Activities (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Number of Stock Options
Number of Options, Options outstanding, beginning of period	611,975
Number of Options, Granted	40,000
Number of Options, Forfeited and cancelled	(10,042)
Number of Options, Options outstanding, end of period	641,933	611,975
Number of Options, Options exercisable, end of period	393,106
Number of Options, Options vested and expected to vest	641,374
Stock Options, Weighted Average Exercise Price
Weighted Average Exercise Price, Options outstanding, beginning of period	$ 6.00
Weighted Average Exercise Price, Granted	0.72
Weighted Average Exercise Price, Forfeited and cancelled	7.54
Weighted Average Exercise Price, Options outstanding, end of period	5.65	$ 6.00
Weighted Average Exercise Price, Options exercisable, end of period	7.51
Weighted Average Exercise Price, Options vested and expected to vest, end of period	$ 5.65
Stock Options, Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term (in years), Options outstanding	7 years 11 months 12 days	8 years 1 month 20 days
Weighted Average Remaining Contractual Term (in years), Options exercisable	7 years 4 months 28 days
Weighted Average Remaining Contractual Term (in years), Options vested and expected to vest	7 years 11 months 12 days