XML 40 R29.htm IDEA: XBRL DOCUMENT v3.19.2
Marketable Securities - Additional Information (Details)
$ in Thousands
6 Months Ended
Jun. 30, 2019
USD ($)
Marketable Securities [Line Items]  
Realized gains or losses recognized on sale or maturity of available-for-sale debt securities $ 0
Impairment charges related to marketable securities $ 0
Maximum  
Marketable Securities [Line Items]  
Marketable securities, contractual maturities 1 year