Note 6 - Stockholders' Equity and Stock-based Compensation (Details Textual) $ / shares in Units, $ in Thousands						1 Months Ended					3 Months Ended		6 Months Ended		12 Months Ended	15 Months Ended
	Feb. 05, 2025 shares	Jan. 01, 2025 shares	Jul. 03, 2024 USD ($) $ / shares shares	Mar. 28, 2024 USD ($) $ / shares shares	Jan. 01, 2024 shares	Jan. 31, 2025 shares	Dec. 31, 2024 $ / shares shares	Mar. 31, 2024 shares	Jan. 31, 2024 shares	Nov. 30, 2017 shares	Jun. 30, 2025 USD ($) $ / shares shares	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) $ / shares shares	Jun. 30, 2024 USD ($)	Dec. 31, 2017 shares	Jun. 30, 2025 USD ($) $ / shares shares
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares							$ 0.001				$ 0.001		$ 0.001			$ 0.001
Equity Classified Subscription, Value | $												$ 47,700		$ 47,700
Right Offering Deemed Dividend | $												47,700	$ 0	47,700
Proceeds from Warrant Exercises | $													14,063	0
Share-Based Payment Arrangement, Expense | $											$ 5,189	2,052	10,870	3,811
Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value | $													$ 18,200
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)													1,200,400
Share-Based Payment Arrangement, Expense | $											3,579	1,315	$ 7,686	2,478
Performance-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value | $													$ 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)													0
Share-Based Payment Arrangement, Expense | $											0	14	$ 0	22
Market-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value | $													$ 3,700
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)													232,500
Share-Based Payment Arrangement, Expense | $											1,535	$ 683	$ 3,004	$ 1,190
Performance-based and Market-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Intrinsic Value | $													$ 18,900
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)													1,200,000
Share-Based Payment Arrangement, Expense | $											$ 0		$ 0
The 2017 Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)															10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)															1,500,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)		1,200,000			1,200,000		1,375,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares)															1,200,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent															4.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)											0		0			0
The 2017 Inducement Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)										10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)										1,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)								2,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)											2,355,726		2,355,726			2,355,726
The 2017 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)															250,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)						450,000			450,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Number of Shares (in shares)															450,000
Increase in Shares Available for Issuance, Threshold of Common Stock Outstanding, Percent															1.50%
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)											869,935		869,935			869,935
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)													25,844
Share-Based Payment Arrangement, Tranche One [Member] | Time-based Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage													25.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)													1 year
Share-Based Payment Arrangement, Tranche One [Member] | The 2017 Inducement Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage										25.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)										1 year
Maximum [Member] | The 2017 Inducement Equity Incentive Plan [Member] | Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)										10 years
Warrants Issued in 2024 Rights Offering [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)			0.5	0.5
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			5,999,999
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares			$ 11
Class of Warrans or Right, Exercise Price, Percentage of Subscription Price for Units			110.00%
Warrants and Rights Outstanding, Term (Year)			5 years
Proceeds from Warrant Exercises | $													$ 14,000			$ 63,500
Warrants Issued in 2024 Rights Offering [Member] | Vesting of First Half [Member]
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) | $ / shares			$ 0.01
Class of Warrant or Right, Percentage Required for Redemption	150.00%		150.00%								150.00%		150.00%			150.00%
Class of Warrant or Right, Vesting, Stock Price Trigger (in dollars per share) | $ / shares			$ 16.5								$ 18.85		$ 18.85			$ 18.85
Class of Warrant or Right, Expired/Redeemed During Period (in shares)	18,221
Class of Warrant or Right, Outstanding (in shares)	0										0		0			0
Warrants Issued in 2024 Rights Offering [Member] | Vesting of Second Half [Member]
Class of Warrants or Rights, Redemption Price Per Share (in dollars per share) | $ / shares			$ 0.01
Class of Warrant or Right, Percentage Required for Redemption			200.00%								200.00%		200.00%			200.00%
Class of Warrant or Right, Vesting, Stock Price Trigger (in dollars per share) | $ / shares			$ 22
Class of Warrant or Right, Outstanding (in shares)											208,406		208,406			208,406
Warrants Issued in 2024 Rights Offering [Member] | Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			6,000,000
The 2024 Right Offering [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares			$ 0.001	$ 0.001
Equity Offering, Units, Maximum Amount Authorized (in shares)			6,000,000	6,000,000
Equity Offering Units, Offering Value | $				$ 60,000
Shares Issued, Price Per Share (in dollars per share) | $ / shares			$ 10	$ 10
Subscription Right, Number of Units				0.10864186
Number of Shares Per Unit Issued (in shares)			1	1
Number of Warrants in Each Unit (in shares)			2	2
Share Price (in dollars per share) | $ / shares				$ 11.55
Equity Classified Subscription, Value | $				$ 47,700
Right Offering Deemed Dividend | $				$ 47,700
Stock Issued During Period, Shares, New Issues (in shares)			5,999,998
Proceeds from Issuance or Sale of Equity | $			$ 60,000
The 2024 Right Offering [Member] | Majority Stockholder and Co-chairman [Member]
Percent of Offering Purchased			88.00%