Leases - Additional Information (Details) - USD ($)	1 Months Ended			3 Months Ended
	Nov. 30, 2019	Apr. 30, 2018	Sep. 30, 2017	Mar. 31, 2021
Lessee Lease Description [Line Items]
Operating leases, existence of option to extend				true
Operating leases, options to extend lease term, description				UPL signed an addendum to its November 2014 lease agreement for the Company’s executive offices located in Israel, in order to increase the office space rented and to extend the rent period until 2019. In March 2019, UPL utilized the agreement extension option and extended the rent period for additional three years until August 2022.
Operating leases, options to extend lease term				3 years
Operating lease extended lease expiration, month and year				2022-08
Remaining rental payments to be received over the lease term				$ 56,000
Impairment losses on operating leases				$ 0
Minimum
Lessee Lease Description [Line Items]
Lease expiration year				2021
Maximum
Lessee Lease Description [Line Items]
Lease expiration year				2024
New York | UroGen Pharma Inc.
Lessee Lease Description [Line Items]
Lease commencement period, month and year			2017-10
Lease termination period, month and year			2021-02
Los Angeles, California | UroGen Pharma Inc.
Lessee Lease Description [Line Items]
Lease termination period, month and year		2024-03
Lease commencement date		Jul. 10, 2018
Proceeds from tenant allowance		$ 200,000
Remaining contractual obligation				$ 800,000
Lessee operating sublease commencement date	Jan. 01, 2020
Lessee operating sublease termination period, month and year	2024-03
Remaining rental payments to be received over the lease term				700,000
Princeton, NJ | UroGen Pharma Inc. | Lease Agreement
Lessee Lease Description [Line Items]
Lease commencement date	Nov. 29, 2019
Remaining contractual obligation				$ 1,000,000.0
Lease term	38 months