Clearfield, Inc. Quarterly report pursuant to Section 13 or 15(d)

Note 5 - Fair Value Measurements - Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
Cash equivalents	$ 25,328	$ 26,467
Investment securities:	134,857	136,629
Fair Value, Inputs, Level 1 [Member]
Cash equivalents	25,328	26,467
Investment securities:	0	0
Fair Value, Inputs, Level 2 [Member]
Cash equivalents	0	0
Investment securities:	134,857	136,629
Fair Value, Inputs, Level 3 [Member]
Cash equivalents	0	0
Investment securities:	0	0
Money Market Funds [Member]
Cash equivalents	25,328	26,467
Money Market Funds [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash equivalents	25,328	26,467
Money Market Funds [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash equivalents	0	0
Money Market Funds [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash equivalents	0	0
Certificates of Deposit [Member]
Investment securities:	130,229	8,115
Certificates of Deposit [Member] \| Fair Value, Inputs, Level 1 [Member]
Investment securities:	0	0
Certificates of Deposit [Member] \| Fair Value, Inputs, Level 2 [Member]
Investment securities:	130,229	8,115
Certificates of Deposit [Member] \| Fair Value, Inputs, Level 3 [Member]
Investment securities:	0	0
US Treasury Securities [Member]
Investment securities:	4,628	128,514
US Treasury Securities [Member] \| Fair Value, Inputs, Level 1 [Member]
Investment securities:	0	0
US Treasury Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Investment securities:	4,628	128,514
US Treasury Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Investment securities:	$ 0	$ 0