Annual report pursuant to Section 13 and 15(d)

Cash Equivalents and Marketable Securities - Additional Information (Details)

v3.19.1
Cash Equivalents and Marketable Securities - Additional Information (Details)
12 Months Ended
Dec. 31, 2018
USD ($)
Maximum  
Cash And Cash Equivalents [Line Items]  
Marketable securities maturity period 1 year
Marketable Securities  
Cash And Cash Equivalents [Line Items]  
Recognition of other-than-temporary impairment $ 0