Consolidated Statements of Operations - USD ($)	12 Months Ended
	Jul. 31, 2023	Jul. 31, 2022	Jul. 31, 2021
Income Statement [Abstract]
Net sales	$ 549,994,000	$ 486,239,000	$ 581,695,000
Cost of sales	365,534,000	306,403,000	367,737,000
Gross profit	184,460,000	179,836,000	213,958,000
Expenses:
Selling, general and administrative	120,003,000	114,858,000	111,796,000
Research and development	48,631,000	52,532,000	49,148,000
Amortization of intangibles	21,396,000	21,396,000	21,020,000
CEO transition costs	9,090,000	13,554,000	0
Proxy solicitation costs	0	11,248,000	0
Acquisition plan expenses	0	0	100,292,000
Total operating expenses	199,120,000	213,588,000	282,256,000
Operating loss	(14,660,000)	(33,752,000)	(68,298,000)
Other expenses (income):
Interest expense	14,961,000	5,031,000	6,821,000
Interest (income) and other	1,226,000	(703,000)	(139,000)
Change in fair value of convertible preferred stock purchase option liability	0	(1,005,000)	0
Loss before benefit from income taxes	(30,847,000)	(37,075,000)	(74,980,000)
Benefit from income taxes	(3,948,000)	(4,023,000)	(1,500,000)
Net loss	(26,899,000)	(33,052,000)	(73,480,000)
Convertible preferred stock issuance costs	0	(4,007,000)	0
Establishment of initial convertible preferred stock purchase option liability	0	(1,005,000)	0
Dividend on convertible preferred stock	(7,007,000)	(5,204,000)	0
Net loss attributable to common stockholders	$ (33,906,000)	$ (43,268,000)	$ (73,480,000)
Net loss per share:
Basic (in dollars per share)	$ (1.21)	$ (1.63)	$ (2.86)
Diluted (in dollars per share)	$ (1.21)	$ (1.63)	$ (2.86)
Weighted average number of common shares outstanding - basic (in shares)	28,002,000	26,506,000	25,685,000
Weighted average number of common and common equivalent shares outstanding - diluted (in shares)	28,002,000	26,506,000	25,685,000