Description of Business and Basis of Presentation (Details) ft² in Thousands, $ in Thousands	Mar. 31, 2022 USD ($) ft²
Accounting Policies [Abstract]
Facility size (in square feet) \| ft²	30
Accumulated deficit generated, since inception	$ 197,252
Cash, cash equivalents, short-term investments, and restricted cash	$ 27,584

Cash, Cash Equivalents, Short-Term Investments, And Restricted Cash

No definition available.

Name:	xcur_CashCashEquivalentsShortTermInvestmentsAndRestrictedCash
Namespace Prefix:	xcur_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant