Note 7 - Collaborative Agreements (Details Textual) $ in Thousands	3 Months Ended
Jun. 30, 2023 USD ($)
Collaborative Arrangement, Transaction with Party to Collaborative Arrangement [Member] \| Cancer Research Horizons [Member]
Revenue from Collaborative Arrangement, Excluding Revenue from Contract with Customer	$ 0

Amount of revenue from collaborative arrangement. Excludes revenue from contract with customer under Topic 606.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 808
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479402/808-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-SubTopic 10
-Topic 808
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479428/808-10-45-3

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration