Retirement Plan (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Matching percentage of company of every dollar contributed (as a percent)	100.00%
Maximum annual contribution (as a percent)	3.00%
Additional matching contribution (as a percent)	50.00%
Additional percentage of compensation subject to matching contribution (as a percent)	2.00%
Maximum company match (as a percent)	4.00%
Company contributions	$ 4.9	$ 4.4	$ 2.7

Defined contribution plan additional maximum annual contributions per employee percent.

No definition available.

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Period Type:	duration

Defined contribution plan employer matching additional contribution upon employee percent.

No definition available.

Name:	neo_DefinedContributionPlanEmployerMatchingAdditionalContributionUponEmployeePercent
Namespace Prefix:	neo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_CompensationAndRetirementDisclosureAbstract
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Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage employer matches of the employee's percentage contribution matched.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration