Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	85,000,000
Common stock, shares issued (in shares)	68,153,336	64,171,435
Common stock, shares outstanding (in shares)	68,120,003	64,138,102
Treasury stock, at cost, shares (in shares)	33,333	33,333