Share based compensation arrangement by share based payment award exercised options outstanding number.

No definition available.

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- Definition

Share based compensation arrangement by share based payment award vesting frequency of period.

+ References

No definition available.

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- Definition

Stock issued during period shares, warrants exercised.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

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- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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- Definition

Face amount or stated value per share of common stock.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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- Definition

Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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Stockholder's Equity (Deficit) - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	May 31, 2015
Class Of Stock [Line Items]
Common stock, shares authorized	190,000,000		190,000,000		190,000,000
Common stock, par value	$ 0.000004		$ 0.000004		$ 0.000004
Stock issued on exercise of warrants		2,534,239	67,713	2,534,239
Total unrecognized stock compensation expense related to unvested options and restricted stock granted under the Plans	$ 15.0	$ 10.4	$ 15.0	$ 10.4
Unrecognized expense expected to be recognized period			3 years
Montrose Amended & Restated 2017 Stock Incentive Plan
Class Of Stock [Line Items]
Restricted shares outstanding	286,239	267,173	286,239	267,173
Restricted shares forfeited	0	0	0	1,667
Montrose Amended & Restated 2017 Stock Incentive Plan \| Restricted Stock
Class Of Stock [Line Items]
Restricted shares became fully vested and released as common stock	0	0	38,929	10,000
Montrose Amended & Restated 2017 Stock Incentive Plan \| Stock Options \| Board of Directors
Class Of Stock [Line Items]
Shares of vested over period			4 years
Montrose Amended & Restated 2017 Stock Incentive Plan \| Stock Options \| Executive Officers
Class Of Stock [Line Items]
Shares of vested over period			3 years
Vesting frequency of period			1 year
Montrose Amended & Restated 2017 Stock Incentive Plan \| Stock Options \| Second Anniversary \| Board of Directors
Class Of Stock [Line Items]
Award vesting percentage			50.00%
Montrose Amended & Restated 2017 Stock Incentive Plan \| Stock Options \| Fourth Anniversary \| Board of Directors
Class Of Stock [Line Items]
Award vesting percentage			50.00%
Montrose Amended and Restated 2013 Stock Option Plan
Class Of Stock [Line Items]
Shares outstanding from exercised options	1,028,268	221,950	1,028,268	221,950
Private Offering
Class Of Stock [Line Items]
Warrants to purchase common stock						116,350
Warrant exercise price per share						$ 17.19