STOCKHOLDERS' EQUITY - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Aug. 31, 2020	Aug. 31, 2019	Aug. 31, 2018	Aug. 31, 2020	Aug. 31, 2019
Stock Options
Balance Outstanding				14,761,000	9,368,000
Granted				6,250,000	10,082,000
Exercised				(9,000)	(502,000)
Forfeited				(10,358,000)	(4,187,000)
Balance Outstanding		14,761,000	9,368,000		14,761,000
Weighted Average Exercise Price
Balance Outstanding				$ 4.89	$ 3.85
Granted				1.20	5.50
Exercised				2.06	1.20
Forfeited				4.68	4.46
Balance Outstanding	$ 1.58	$ 4.89	$ 3.85	$ 1.58	$ 4.89
Vested and expected to vest	8,709,000			8,709,000
Vested and expected to vest (in dollars per share)	$ 1.74			$ 1.74
Exercisable	5,806,000			5,806,000
Exercisable (in dollars per share)	$ 2.19			$ 2.19
Weighted Average Remaining Contractual Term Outstanding (in years)	8 years 6 months	9 years	9 years 1 month 6 days
Vested and expected to vest (in years)	8 years 3 months 18 days
Weighted Average Remaining Contractual Term Exercisable (in years)	7 years 10 months 24 days
Aggregate Intrinsic Value, Balance Outstanding	$ 232	$ 3,192	$ 14,463	$ 232	$ 3,192
Aggregate Intrinsic Value, Exercised				14	$ 2,576
Aggregate Intrinsic Value, Vested and expected to vest	183			183
Aggregate Intrinsic Value Exercisable	$ 108			$ 108