Annual report pursuant to Section 13 and 15(d)

Cash Equivalents and Marketable Securities - Additional Information (Details)

v3.20.1
Cash Equivalents and Marketable Securities - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Cash And Cash Equivalents [Line Items]    
Long-term marketable securities $ 15,609,000 $ 0
Investments in an unrealized loss position 4,500,000 52,600,000
Recognition of other-than-temporary impairment $ 0 $ 0
Maximum [Member]    
Cash And Cash Equivalents [Line Items]    
Marketable securities maturity period 1 year 1 year