Note 2 - Significant Accounting Policies - Tax Returns Subject to Examination (Details)	3 Months Ended
Jun. 30, 2021
Domestic Tax Authority [Member]
Open tax year	2016 2017 2018 2019 2020 2021
State and Local Jurisdiction [Member] \| New Jersey Division of Taxation [Member]
Open tax year	2015 2016 2017 2018 2019 2020 2021

Tax year that remains open to examination under enacted tax laws, in YYYY format.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

Name:	us-gaap_OpenTaxYear
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:gYearListItemType
Balance Type:	na
Period Type:	duration