XML 53 R41.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation - Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan
$ in Millions
3 Months Ended
Mar. 31, 2018
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Unrecognized compensation expense $ 0.3
Unrecognized compensation expense, period for recognition (years) 3 months 18 days