Note 13 - Fair Value Measurements (Details) - Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation - Fair Value, Inputs, Level 3 [Member]	3 Months Ended
	Jun. 30, 2018 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 0
Gains and losses for the period (realized and unrealized)	0
Purchases, issuances, sales and settlements, net	0
Transfers in or out of Level 3	0
Balance at the end of period	0
Warrant [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	0
Gains and losses for the period (realized and unrealized)	0
Purchases, issuances, sales and settlements, net	0
Transfers in or out of Level 3	0
Balance at the end of period	$ 0