CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Jul. 31, 2019		61,805,856
Beginning balance at Jul. 31, 2019	$ 52,692	$ 618	$ 7,477,327	$ (7,426,287)	$ 1,034
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(4,924)			(4,924)
Preferred dividends	(1,592)			(1,592)
Issuance of common stock pursuant to employee stock purchase plan (in shares)		17,299
Issuance of common stock pursuant to employee stock purchase plan	8		8
Restricted stock grants (in shares)		560,523
Restricted stock grants	0	$ 6	(6)
Share-based compensation	581		581
Other comprehensive items	(2,614)				(2,614)
Ending balance (in shares) at Apr. 30, 2020		62,383,678
Ending balance at Apr. 30, 2020	44,151	$ 624	7,477,910	(7,432,803)	(1,580)
Beginning balance (in shares) at Jan. 31, 2020		62,375,558
Beginning balance at Jan. 31, 2020	53,815	$ 624	7,477,697	(7,426,119)	1,613
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(6,159)			(6,159)
Preferred dividends	(525)			(525)
Issuance of common stock pursuant to employee stock purchase plan (in shares)		8,120
Issuance of common stock pursuant to employee stock purchase plan	4		4
Share-based compensation	209		209
Other comprehensive items	(3,193)				(3,193)
Ending balance (in shares) at Apr. 30, 2020		62,383,678
Ending balance at Apr. 30, 2020	$ 44,151	$ 624	7,477,910	(7,432,803)	(1,580)
Beginning balance (in shares) at Jul. 31, 2020	62,787,919	62,787,919
Beginning balance at Jul. 31, 2020	$ 48,818	$ 628	7,478,047	(7,433,700)	3,843
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(33,376)			(33,376)
Preferred dividends	(1,586)			(1,586)
Issuance of common stock pursuant to employee stock purchase plan (in shares)		8,792
Issuance of common stock pursuant to employee stock purchase plan	4		4
Restricted stock grants (in shares)		332,578
Restricted stock grants	0	$ 3	(3)
Restricted stock forfeitures (in shares)		(32,895)
Share-based compensation	443		443
Other comprehensive items	$ 5,281				5,281
Ending balance (in shares) at Apr. 30, 2021	63,096,394	63,096,394
Ending balance at Apr. 30, 2021	$ 19,584	$ 631	7,478,491	(7,468,662)	9,124
Beginning balance (in shares) at Jan. 31, 2021		63,000,314
Beginning balance at Jan. 31, 2021	47,747	$ 630	7,478,395	(7,440,514)	9,236
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(27,629)			(27,629)
Preferred dividends	(519)			(519)
Issuance of common stock pursuant to employee stock purchase plan (in shares)		362
Restricted stock grants (in shares)		95,718
Restricted stock grants	0	$ 1	(1)
Share-based compensation	97		97
Other comprehensive items	$ (112)				(112)
Ending balance (in shares) at Apr. 30, 2021	63,096,394	63,096,394
Ending balance at Apr. 30, 2021	$ 19,584	$ 631	$ 7,478,491	$ (7,468,662)	$ 9,124