Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (20,732)	$ (2,673)
Stock-based compensation	8,144	4,492
Depreciation and amortization	1,848	1,260
Amortization/(accretion) of note premiums	(302)	177
Changes in operating assets and liabilities:
Accounts receivable	(8,157)	(684)
Prepaid expenses and other current assets	(3,193)	1,378
Deferred revenue	(12,547)	(28,771)
Accounts payable	(2,002)	4,552
Accrued expenses	(1,126)	(4,214)
Other	(855)	953
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	(38,922)	(23,530)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(4,271)	(4,320)
Proceeds from sale of marketable securities	34,429	13,600
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	30,158	9,280
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from the exercises of stock options	5,102	3,001
Proceeds from the issuance of common stock		250,477
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	5,102	253,478
NET INCREASE (DECREASE) IN CASH	(3,662)	239,228
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	143,583	221,804
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 139,921	$ 461,032