Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation - Stock Option Activity - Additional Information (Details)

v3.19.1
Stock-based Compensation - Stock Option Activity - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Total fair value of shares vested during the year $ 1.8 $ 1.6
Total unrecognized compensation cost related to unvested share-based compensation arrangements $ 2.1  
Total unrecognized compensation cost related to unvested share-based compensation arrangements, recognition period 2 years 1 month 24 days