Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended
	Oct. 31, 2022	Oct. 31, 2021
Income Statement [Abstract]
Net sales	$ 131,139,000	$ 116,759,000
Cost of sales	84,336,000	75,024,000
Gross profit	46,803,000	41,735,000
Expenses:
Selling, general and administrative	29,337,000	28,242,000
Research and development	12,751,000	12,497,000
Amortization of intangibles	5,349,000	5,349,000
CEO transition costs	9,090,000	0
Proxy solicitation costs	0	2,162,000
Total operating expenses	56,527,000	48,250,000
Operating loss	(9,724,000)	(6,515,000)
Other expenses (income):
Interest expense	2,235,000	1,607,000
Interest (income) and other	(255,000)	219,000
Change in fair value of convertible preferred stock purchase option liability	0	(304,000)
Loss before benefit from income taxes	(11,704,000)	(8,037,000)
Benefit from income taxes	(608,000)	(2,053,000)
Net loss	(11,096,000)	(5,984,000)
Dividend on convertible preferred stock	(1,710,000)	(235,000)
Convertible preferred stock issuance costs	0	(4,007,000)
Establishment of initial convertible preferred stock purchase option liability	0	(1,005,000)
Net loss attributable to common stockholders	$ (12,806,000)	$ (11,231,000)
Net loss per common share (See Note 5):
Basic (in dollars per share)	$ (0.46)	$ (0.43)
Diluted (in dollars per share)	$ (0.46)	$ (0.43)
Weighted average number of common shares outstanding - basic (in shares)	27,830,000	26,426,000
Weighted average number of common and common equivalent shares outstanding - diluted (in shares)	27,830,000	26,426,000