Income Taxes - Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Jul. 31, 2021	Aug. 01, 2020	Aug. 03, 2019
Deferred tax assets:
Inventory reserve and UNICAP	$ 23,007	$ 17,015	$ 11,696
Deferred rent	0	0	232
Accruals and reserves	5,997	4,632	6,623
Research and development credits	27,964	11,611	4,778
Stock-based compensation	17,062	11,717	6,195
Deferred revenue	276	435	713
Operating lease liability	35,969	39,380	0
Net operating losses	10,136	739	0
Other	1,105	349	302
Gross deferred tax assets	121,516	85,878	30,539
Less: valuation allowance	(77,604)	(43,153)	0
Deferred tax assets, net of valuation allowance	43,912	42,725	30,539
Deferred tax liabilities:
Depreciation and amortization	(13,110)	(11,044)	(8,275)
Operating lease right-of-use assets	(28,607)	(31,267)	0
Other	(1,907)	(81)	(89)
Gross deferred tax liabilities	(43,624)	(42,392)	(8,364)
Net deferred tax assets, net of valuation allowance	$ 288	$ 333	$ 22,175