Annual report pursuant to Section 13 and 15(d)

Short-term Investments - Additional Information (Details)

v3.19.1
Short-term Investments - Additional Information (Details)
$ in Millions
Dec. 31, 2018
USD ($)
Investments Debt And Equity Securities [Abstract]  
Held-to-maturity investments with contractual maturities less than one year $ 32.7