Note 11 - Fair Value Measurements (Details) - Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	3 Months Ended
	Jun. 30, 2019 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance	$ 43,500
(Gains) and losses for the period (realized and unrealized)	78,500
Purchases, issuances, sales and settlements, net	0
Transfers in or out of Level 3	0
Balance	122,000
Warrant [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance	43,500
(Gains) and losses for the period (realized and unrealized)	78,500
Purchases, issuances, sales and settlements, net	0
Transfers in or out of Level 3	0
Balance	$ 122,000