Quarterly report pursuant to Section 13 or 15(d)

Cash Equivalents and Marketable Securities - Additional Information (Details)

v3.20.1
Cash Equivalents and Marketable Securities - Additional Information (Details) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Cash And Cash Equivalents [Line Items]      
Long-term marketable securities $ 14,191,000   $ 15,609,000
Investments in an unrealized loss position 48,500,000   4,500,000
Unrealized losses 153,000   $ 3,000
Recognition of other-than-temporary impairment $ 0 $ 0  
Maximum [Member]      
Cash And Cash Equivalents [Line Items]      
Marketable securities maturity period 1 year   1 year