Note 7 - Stock-based Compensation (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Sep. 30, 2025
Share-Based Payment Arrangement, Expense	$ 1,271,000	$ 1,080,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 9,948,000	$ 7,913,000	$ 9,948,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 10 months 24 days	2 years 10 months 24 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross	0	38,198
Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 0	$ 30.9
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)	2 years 5 months 8 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value	$ 4,180,548		$ 4,180,548
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number	50,747		50,747
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Settled in Period	33,834
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Market Price Percentage, Offering Date			85.00%
Issuance of common stock under employee stock purchase plan (in shares)	9,668	11,415
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price	$ 24.78	$ 26.35
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant	112,285		112,285
Share-Based Payment Arrangement, Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period		5 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period		3 years
Share-Based Payment Arrangement, Option [Member] \| Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period	3 years
Share-Based Payment Arrangement, Option [Member] \| Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period	5 years
Restricted Stock Units (RSUs) [Member] \| Share-Based Payment Arrangement, Nonemployee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period	1 year	1 year
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period	652	610
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share	$ 30.66	$ 32.74
Restricted Stock Units (RSUs) [Member] \| The 2022 Plan [Member] \| Share-Based Payment Arrangement, Employee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period	3 years	3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period	150,518	104,691
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share	$ 29.36	$ 30.9
Performance Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period		3 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period	69,117	50,747
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number	69,117		69,117	50,747
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Settled in Period	33,834
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights Over 100 Percent, Percentage	100.00%
Granted, weighted average grant date fair value (in dollars per share)	$ 29.36	$ 30.9
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Vested in Period	16,913
Performance Stock Units [Member] \| Share-Based Payment Arrangement, Tranche One [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage	50.00%	50.00%
Performance Stock Units [Member] \| Share-Based Payment Arrangement, Tranche Two [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights Over 100 Percent, Percentage	150.00%	100.00%
Performance Stock Units [Member] \| Share-Based Payment Arrangement, Tranche Three [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights Over 100 Percent, Percentage		150.00%
Selling, General and Administrative Expenses [Member]
Share-Based Payment Arrangement, Expense	$ 1,228,000	$ 1,043,000
Cost of Sales [Member]
Share-Based Payment Arrangement, Expense	$ 43,000	$ 37,000

Clearfield, Inc. 10-Q