CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	$ 107,628	$ 608	$ 7,467,855	$ (7,363,569)	$ 2,734	$ 6,138	$ 6,138
Beginning balance (in shares) at Jul. 31, 2018		60,742,859
Beginning balance at Jul. 31, 2018	107,628	$ 608	7,467,855	(7,363,569)	2,734	6,138	6,138
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(28,745)			(28,745)
Preferred dividends	(1,598)			(1,598)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (in shares)		13,794
Issuance of common stock pursuant to employee stock purchase plan	15		15
Share-based compensation	1,174		1,174
Other comprehensive items	(426)				(426)
Equity portion of convertible note	8,200		8,200
Restricted stock grants (in shares)		1,045,543
Restricted stock grants		$ 10	(10)
Stockholders' Equity Attributable to Parent	92,386	$ 618	7,477,234	(7,387,774)	2,308	6,138	6,138
Ending balance (in shares) at Apr. 30, 2019		61,802,196
Ending balance at Apr. 30, 2019	92,386	$ 618	7,477,234	(7,387,774)	2,308
Beginning balance (in shares) at Jul. 31, 2018		60,742,859
Beginning balance at Jul. 31, 2018	107,628	$ 608	7,467,855	(7,363,569)	2,734	6,138	6,138
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	$ 52,692	$ 618	7,477,327	(7,426,287)	1,034	$ 6,138	$ 6,138
Ending balance (in shares) at Jul. 31, 2019	61,805,856	61,805,856
Ending balance at Jul. 31, 2019	$ 52,692	$ 618	7,477,327	(7,426,287)	1,034
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	94,537	$ 618	7,468,628	(7,377,622)	2,913
Beginning balance (in shares) at Jan. 31, 2019		61,797,807
Beginning balance at Jan. 31, 2019	94,537	$ 618	7,468,628	(7,377,622)	2,913
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(9,627)			(9,627)
Preferred dividends	(525)			(525)
Preferred dividends	(525)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (in shares)		4,389
Issuance of common stock pursuant to employee stock purchase plan	2		2
Share-based compensation	404		404
Other comprehensive items	(605)				(605)
Equity portion of convertible note	8,200		8,200
Stockholders' Equity Attributable to Parent	92,386	$ 618	7,477,234	(7,387,774)	2,308
Ending balance (in shares) at Apr. 30, 2019		61,802,196
Ending balance at Apr. 30, 2019	92,386	$ 618	7,477,234	(7,387,774)	2,308
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	92,386	618	7,477,234	(7,387,774)	2,308
Stockholders' Equity Attributable to Parent	$ 52,692	$ 618	7,477,327	(7,426,287)	1,034
Beginning balance (in shares) at Jul. 31, 2019	61,805,856	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 and stock option exercises (in shares)		17,299
Issuance of common stock pursuant to employee stock purchase plan	8		8
Share-based compensation	581		581
Other comprehensive items	(2,614)				(2,614)
Restricted stock grants (in shares)		560,523
Restricted stock grants		$ 6	(6)
Stockholders' Equity Attributable to Parent	$ 44,151	$ 624	7,477,910	(7,432,803)	(1,580)
Ending balance (in shares) at Apr. 30, 2020	62,383,678	62,383,678.000
Ending balance at Apr. 30, 2020	$ 44,151	$ 624	7,477,910	(7,432,803)	(1,580)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	53,815	$ 624	7,477,697	(7,426,119)	1,613
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)
Preferred dividends	(525)
Issuance of common stock pursuant to employee stock purchase plan and stock option exercises (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)
Stockholders' Equity Attributable to Parent	$ 44,151	$ 624	7,477,910	(7,432,803)	(1,580)
Ending balance (in shares) at Apr. 30, 2020	62,383,678	62,383,678.000
Ending balance at Apr. 30, 2020	$ 44,151	$ 624	7,477,910	(7,432,803)	(1,580)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	$ 44,151	$ 624	$ 7,477,910	$ (7,432,803)	$ (1,580)