Subsequent Event (Details) - Subsequent Event [Member] $ in Millions	Jan. 01, 2022 USD ($) m²
Subsequent Event (Details) [Line Items]
Rentable square feet \| m²	5,611
Additional lease payments for extra space \| $	$ 1.8

The amount of additional lease payments for extra space.

No definition available.

Name:	jspr_AdditionalLeasePaymentsForExtraSpace
Namespace Prefix:	jspr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration