Stockholders' Equity - Summary of Option Activity under 2010 Plan and 2013 Plan (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 2017
Options
Number of Shares, Options outstanding at beginning of period		463,600
Number of Shares, Options granted	0	202,500
Number of Shares, Options outstanding at end of period		666,100	463,600
Number of Shares, Options exercisable at end of period		169,447
Weighted Average Exercise Price, Options
Weighted Average Exercise Price, Options outstanding at beginning of period		$ 11.23
Weighted Average Exercise Price, Options granted		18.47
Weighted Average Exercise Price, Options outstanding at end of period		12.84	$ 11.23
Weighted Average Exercise Price, Options exercisable at end of period		$ 4.22
Weighted Average Remaining Contract Term, Options
Weighted Average Remaining Contractual Term, Options outstanding at beginning of period		9 years 1 month 6 days	9 years 6 months
Weighted Average Remaining Contractual Term, Options exercisable at end of period		8 years
Aggregate Intrinsic Value, Options outstanding at end of period		$ 5.7
Aggregate Intrinsic Value, Options excersiable at end of period		$ 2.9