Note 4 - Stock-based Compensation - Nonvested Award Activity (Details) - Stock Unit Award [Member] $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares
Outstanding & Unvested at beginning of period (in shares) | shares	24
Outstanding & Unvested at beginning of period, weighted average price per share (in dollars per share) | $ / shares	$ 12.84	[1]
Outstanding & Unvested at beginning of period, weighted average fair value | $	$ 311
Granted (in shares) | shares
Granted, weighted average price per share (in dollars per share) | $ / shares		[1]
Granted, weighted average fair value | $
Converted to common stock (in shares) | shares	(10)
Converted to common stock, weighted average price per share (in dollars per share) | $ / shares	$ 20.24	[1]
Converted to common stock, weighted average fair value | $
Cancelled (in shares) | shares	(1)
Cancelled, weighted average price per share (in dollars per share) | $ / shares	$ 20.24	[1]
Cancelled, weighted average fair value | $
Forfeited (in shares) | shares
Forfeited, weighted average price per share (in dollars per share) | $ / shares		[1]
Forfeited, weighted average fair value | $
Outstanding & Unvested at end of period (in shares) | shares	13
Outstanding & Unvested at end of period, weighted average price per share (in dollars per share) | $ / shares	$ 11.87	[1]
Outstanding & Unvested at end of period, weighted average fair value | $	$ 156

[1] Weighted average price per share is the weighted grant price based on the closing market price of each of the stock grants related to each grant of stock unit awards. The weighted average fair value is the weighted average share price times the number of shares.