Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (27,198)	$ 20,732	$ (26,743)
Other comprehensive income (loss):
Foreign currency translation adjustments	518	(1,841)	(1,567)
Unrealized gains (losses) on available-for-sale securities	2,138	2,956	(596)
Tax benefit (expense) on unrealized gains (losses) on available-for-sale securities	(669)	(573)	233
Reclassification adjustment for realized gains (losses) included in net income (loss)	632	(552)	(22)
Total other comprehensive income (loss)	2,619	(10)	(1,952)
Comprehensive income (loss)	$ (24,579)	$ 20,722	$ (28,695)