Stockholders' Equity - Summary of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	$ 3,688	$ 854	$ 1,868
Performance-based RSUs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	1,762	413	1,498
Time-based RSUs and restricted stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	1,862	418	370
ESPP
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock based compensation	$ 64	$ 23	$ 0