Summary of significant accounting policies (Tables)

12 Months Ended

Jul. 31, 2020

Accounting Policies [Abstract]

Schedule of net accounts receivable by segment

	July 31, 2020					July 31, 2019
Net accounts receivable by segment	Amount		%			Amount		%
Clinical Labs (by billing category)
Third party payers	$	2,455		40		$	2,956		44
Patient self-pay		2,044		33			2,360		35
Medicare		884		14			910		13
HMO’s		797		13			574		8
Total Clinical Labs		6,180		100	%		6,800		100	%
Total Life Sciences		2,961					3,938
Total accounts receivable – net	$	9,141				$	10,738

Schedule of basic and diluted net income (loss) per share

	2020			2019		2018
Net (loss) income	$	(28,520	)	$	2,489	$	(10,321	)
Weighted-average common shares outstanding - basic		47,696			47,351		46,972
Add: effect of dilutive stock options and restricted stock		—			125		—
Weighted-average common shares outstanding - diluted		47,696			47,476		46,972
Net (loss) income per share – basic	$	(0.60	)	$	0.05	$	(0.22	)
Net (loss) income per share – diluted	$	(0.60	)	$	0.05	$	(0.22	)

Schedule of expense related to share-based payment arrangements

	2020		2019		2018
Cost of clinical laboratory services	$	46	$	—	$	—
Selling, general and administrative		887		939		813
	$	933	$	939	$	813

Schedule of adoption of the standard on prior period consolidated operations, cash flows and balance sheet

Consolidated Statements of Operations for fiscal year ended July 31, 2018:	As Previously Reported			Adjustment for New Accounting Standard on Revenue Recognition			Reclassification of Residual			As Restated
Total Revenues	$	104,713		($	3,700	)		—		$	101,013
Provision for uncollectible accounts receivable		3,690			(3,700	)	$	10			—
Selling, general and administrative expenses		44,465			—			(10	)		44,455
Net loss		(10,321	)		—			—			(10,321	)

Consolidated Statements of Cash Flows July 31, 2018:	As Previously Reported			Adjustment for New Accounting Standard on Revenue Recognition			Reclassification of Residual			As Restated
Provision for uncollectible accounts receivable		3,690			(3,700	)		10			—
Changes in operating assets and liabilities: Accounts receivable		(1,775	)		3,700			(10	)		1,915
Consolidated balance sheet July 31, 2018:
Accounts receivable		15,815			(2,523	)		—			13,292
Less: Allowance for doubtful accounts		2,668			(2,523	)		—			145
Accounts receivable, net of allowance for doubtful accounts		13,147			—			—			13,147