Note 4 - Grant Income (Details Textual) - Jun. 30, 2021 € in Millions, $ in Millions	USD ($)	EUR (€)
Grants Receivable	$ 17	€ 14.2

Carrying amount as of the balance sheet date of amounts due under the terms of governmental, corporate, or foundation grants.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(4))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_GrantsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant