Note 10 - Commitments and Contingencies (Details Textual) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Clinical Collaborations [Member] \| Maximum [Member]
Clinical Milestones Payment in Cash and Shares of Common Stock	$ 9.5	$ 9.5

Amount of payment in cash and common stock shares for achievement of clinical milestones.

No definition available.

Name:	pyxs_ClinicalMilestonesPaymentInCashAndSharesOfCommonStock
Namespace Prefix:	pyxs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration