Note 7 - Commitments and Contingencies (Tables)
|6 Months Ended|
Jun. 30, 2021
|Lease, Cost [Table Text Block]||
Tabular disclosure of lessee's lease cost. Includes, but is not limited to, interest expense for finance lease, amortization of right-of-use asset for finance lease, operating lease cost, short-term lease cost, variable lease cost and sublease income.
Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef