Note 10 - Stockholders' Equity (Details Textual) - $ / shares	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Common Stock, Shares Authorized (in shares)	150,000,000	150,000,000	150,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Preferred Stock, Shares Authorized (in shares)	5,000,000	5,000,000	5,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001