Fair Value Disclosures (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 0	$ 0
Transfers of assets between fair value hierarchy levels	0	0
Fair Value Measurements, Recurring | Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents consisting of money market funds and commercial paper	$ 6,700,000	$ 8,300,000