STOCKHOLDERS' EQUITY - OSI Plans (Details) - USD ($)	1 Months Ended	12 Months Ended
STOCKHOLDERS' EQUITY - OSI Plans (Details) - USD ($)	Dec. 31, 2023	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected holding period (in years)		4 years 6 months	4 years 6 months	4 years 6 months
Weighted-Average Fair Value
Granted (in dollars per share)		$ 127.88	$ 95.42	$ 87.9
Share Based Employee Compensation Plans [Member]
Weighted-Average Fair Value
Additional maximum number of shares of common stock which may be issued	2,400,000
Increase in maximum number of shares authorized under share based compensation plan	9,500,000
Shares available for grant		2,000,000
Share Based Employee Compensation Plans [Member] \| Minimum
Weighted-Average Fair Value
Purchase price expressed as a percentage of the fair market value of the Company's common stock on the date of grant		110.00%
Share based compensation arrangement byshare based payment award percentage of voting power owned		10.00%
Share Based Employee Compensation Plans [Member] \| Employee Stock Option
Number of Options
Outstanding at the beginning of the period (in shares)		78,958	83,677	110,645
Granted (in shares)		16,039	22,438	23,351
Exercised (in shares)		(33,782)	(22,698)	(47,354)
Expired or forfeited (in shares)		(962)	(4,459)	(2,965)
Outstanding at the end of the period (in shares)		60,253	78,958	83,677
Exercisable at the end of the period (in shares)		22,602
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)		$ 97.87	$ 87.09	$ 82.43
Granted (in dollars per share)		174.09	119.45	87.9
Exercised (in dollars per share)		91.69	81.67	77.42
Expired or forfeited (in dollars per share)		111.09	86.72	74.06
Outstanding at the end of the period (in dollars per share)		121.41	$ 97.87	$ 87.09
Exercisable at the end of the period (in dollars per share)		$ 96.15
Weighted-Average Remaining Contractual Term
Outstanding at the end of the period		7 years 9 months 18 days
Exercisable at the end of the period		6 years 4 months 24 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Risk-free interest rate (as percent)		4.40%	4.50%	3.90%
Expected volatility (as percent)		29.00%	29.00%	31.00%
Aggregate Intrinsic Value
Outstanding at the end of the period		$ 6,233,000
Exercisable at the end of the period		$ 2,909,000
Stock-based compensation, other disclosures
Weighted-average grant-date fair value of stock options (in dollars per share)		$ 55.5	$ 38.28	$ 28.46
Total intrinsic value of options exercised		$ 3,200,000
Weighted-Average Fair Value
Vesting period		3 years
Share Based Employee Compensation Plans [Member] \| Restricted Stock And Restricted Stock Units
Shares
Nonvested at the beginning of the period (in shares)		391,591	455,515	427,447
Granted (in shares)		297,912	333,114	357,475
Vested (in shares)		(323,297)	(390,375)	(313,862)
Forfeited (in shares)		(10,810)	(6,663)	(15,545)
Nonvested at the end of the period (in shares)		355,396	391,591	455,515
Weighted-Average Fair Value
Nonvested at the beginning of the period (in dollars per share)		$ 99.21	$ 85.15	$ 90.17
Granted (in dollars per share)		150.91	95.42	87.9
Vested (in dollars per share)		127.88	79.75	96.36
Forfeited (in dollars per share)		103.4	88.76	88.42
Nonvested at the end of the period (in dollars per share)		$ 116.34	$ 99.21	$ 85.15
Total fair value of shares vested		$ 41,300,000	$ 31,100,000	$ 30,200,000
Number of shares available for grant reduced for each award granted		1.87
Number of shares available for grant increased for each award forfeited and returned		1.87
Share Based Employee Compensation Plans [Member] \| Restricted Stock And Restricted Stock Units \| Minimum
Weighted-Average Fair Value
Vesting period		3 years
Share Based Employee Compensation Plans [Member] \| Restricted Stock And Restricted Stock Units \| Maximum
Weighted-Average Fair Value
Vesting period		4 years
Share Based Employee Compensation Plans [Member] \| Performance-based restricted stock units
Shares
Granted (in shares)		80,682	75,988	110,811
Share Based Employee Compensation Plans [Member] \| Incentive Stock Options \| Minimum
Weighted-Average Fair Value
Purchase price expressed as a percentage of the fair market value of the Company's common stock on the date of grant		110.00%
Share based compensation arrangement byshare based payment award percentage of voting power owned		10.00%

OSI SYSTEMS INC 10-K