Condensed Consolidated Statements of Operations - USD ($)
 3 Months Ended 9 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Apr. 30, 2017
Apr. 30, 2016
Income Statement [Abstract]        
Net sales $ 127,792,000 $ 124,187,000 $ 402,606,000 $ 258,627,000
Cost of sales 75,331,000 72,796,000 244,833,000 149,596,000
Gross profit 52,461,000 51,391,000 157,773,000 109,031,000
Expenses:        
Selling, general and administrative 25,923,000 30,439,000 89,596,000 60,818,000
Research and development 12,961,000 12,613,000 40,371,000 28,216,000
Amortization of intangibles 5,468,000 4,776,000 17,555,000 7,348,000
Settlement of intellectual property litigation (2,041,000) 0 (12,020,000) 0
Acquisition plan expenses 0 16,960,000 0 20,689,000
Total operating expenses 42,311,000 64,788,000 135,502,000 117,071,000
Operating income (loss) 10,150,000 (13,397,000) 22,271,000 (8,040,000)
Other expenses (income):        
Interest expense and other 2,761,000 3,473,000 8,938,000 3,621,000
Interest income and other (88,000) 5,000 (12,000) 227,000
Income (loss) before provision for (benefit from) income taxes 7,301,000 (16,865,000) 13,321,000 (11,434,000)
Provision for (benefit from) income taxes 2,884,000 (2,510,000) 4,808,000 (994,000)
Net income (loss) $ 4,417,000 $ (14,355,000) $ 8,513,000 $ (10,440,000)
Net income (loss) per share (See Note 5):        
Basic (in dollars per share) $ 0.19 $ (0.89) $ 0.36 $ (0.65)
Diluted (in dollars per share) $ 0.19 $ (0.89) $ 0.36 $ (0.65)
Weighted average number of common shares outstanding – basic (in shares) 23,449,000 16,195,000 23,420,000 16,184,000
Weighted average number of common and common equivalent shares outstanding – diluted (in shares) 23,503,000 16,195,000 23,449,000 16,184,000
Dividends declared per issued and outstanding common share as of the applicable dividend record date (in dollars per share) $ 0.1 $ 0.30 $ 0.5 $ 0.90