Stockholder's Equity (Tables)

3 Months Ended

Mar. 31, 2022

Summary of Issued Shares of Common Stock

The Company issued the following shares of common stock:

	Three Months Ended March 31,
	2022						2021
	Shares		Average Price per Share		Total (in thousands)		Shares		Average Price per Share		Total (in thousands)
Acquisitions		—	$	—	$	—		71,740	$	31.65	$	2,271
Exercise of warrants (1)		—		—		—		67,713		17.19		—
Exercise of options		30,607		14.03		429		330,060		6.62		2,185
Restricted shares, net (1)		25,289		66.58		—		36,817		29.88		—
Total		55,896	$	37.81	$	429		506,330	$	13.27	$	4,456

(1) Represents the release of common shares due to the exercise of warrants options and the vesting of restricted stock.

Schedule of Share Authorized to be Issue and Available for Grant

The following number of shares were authorized to be issued and available for grant:

	March 31, 2022
	2017 Plan		2013 Plan		Total
Shares authorized to be issued		8,272,487		1,904,644		10,177,131
Shares available for grant(1)		577,139		—		577,139
	March 31, 2021
	2017 Plan		2013 Plan		Total
Shares authorized to be issued		3,944,750		2,047,269		5,992,019
Shares available for grant		1,618,996		—		1,618,996

Schedule of Stock Compensation Expense

Total stock compensation expense for the Plans was as follows:

	Three Months Ended March 31,
	2022
	2017 plan						2013 plan
	Options		Restricted Stock		SARs		Options		Total
Cost of revenue	$	294	$	—	$	—	$	—	$	294
Selling, general and    administrative expense		1,979		5,792		2,360		—		10,131
Total	$	2,273	$	5,792	$	2,360	$	—	$	10,425
	Three Months Ended March 31,
	2021
	2017 plan						2013 plan
	Options		Restricted Stock		SARs		Options		Total
Cost of revenue	$	606	$	—	$	—	$	10	$	616
Selling, general and    administrative expense		1,004		182		—		3		1,189
Total	$	1,610	$	182			$	13	$	1,805

Summary of Performance Hurdles

The performance hurdles shall be deemed achieved if the average trading price per share of the Company’s common stock equals or exceeds the following stock prices:

SARs Stock Price Performance Hurdle		Portion of SARs Subject to Performance Hurdle
$	133.58	1/3
$	166.98	1/3
$	200.37	1/3

Summary of Weighted Average Assumptions Used in Black-Sholes Option-pricing Model

The following weighted-average assumptions were used in the Black-Sholes option-pricing model calculation:

	March 31,			March 31,
	2022			2021
Common stock value (per share)	$	44.11		$	37.61
Expected volatility		33.45	%		58.01	%
Risk-free interest rate		1.74	%		0.71	%
Expected life (years)		6.33			6.20
Forfeiture rate	None			None
Dividend rate	None			None

Schedule of Common Stock Reserved for Future Issuance

Common Stock Reserved for Future Issuances—The Company has reserved certain stock of its authorized but unissued common stock for possible future issuance in connection with the following:

	March 31,
	2022		2021
Montrose 2013 Stock Incentive Plan		878,614		2,047,269
Montrose 2017 Stock Incentive Plan(1)		7,893,918		3,944,750
Total		8,772,532		5,992,019

Montrose Amended & Restated 2017 Stock Incentive Plan

Schedule of Restricted Stock Activity

Restricted stock activity was as follows:

	Three Months Ended March 31,
	2022						2021
	Shares		Average Price per Share		Fair Value (in thousands)		Shares		Average Price per Share		Fair Value (in thousands)
Shares granted		106,324	$	46.82	$	4,978		14,532	$	30.96	$	450

Summary of Stock Option Activity

The following summarizes the options activity of the 2017 Plan:

	Options to Purchase Common Stock			Weighted- Average Exercise Price per Share		Weighted Average Grant Date Fair Value per Share		Weighted Average Remaining Contract Life (in Years)		Aggregate Intrinsic Value of In-The- Money Options (in Thousands)
Outstanding at January 1, 2021		1,840,229		$	23	$	12		9.09	$	15,598
Granted		224,270			38		20		—		—
Forfeited/ cancelled		(10,000	)		26		—		—		—
Expired		(1,250	)		18		—		—		—
Exercised		(17,188	)		16		—		—		519
Outstanding at March 31, 2021		2,036,061			24		13		8.97		52,317
Outstanding at January 1, 2022		2,036,729		$	26	$	14		8.30	$	91,030
Granted		547,884			44		16		—		—
Forfeited/ cancelled		(23,082	)		36		—		—		—
Exercised		(11,547	)		27		—		—		313
Outstanding at March 31, 2022		2,549,984		$	30	$	14		8.46	$	59,955
Exercisable at March 31, 2022		515,943			30		—		7.43		12,083
Options vested and expected to vest		2,549,984			30		—		8.46		59,955

Montrose Amended and Restated 2013 Stock Option Plan

Summary of Stock Option Activity

The following summarizes the activity of the 2013 Plan:

	Options to Purchase Common Stock			Weighted- Average Exercise Price per Share		Weighted Average Grant Date Fair Value per Share		Weighted Average Remaining Contract Life (in Years)		Aggregate Intrinsic Value of In-The- Money Options (in Thousands)
Outstanding at January 1, 2021		1,787,869		$	6	$	—		5.40	$	43,867
Exercised		(311,872	)		6		—		—		12,321
Outstanding at March 31, 2021		1,475,997			6		—		5.14		64,492
Outstanding at January 1, 2022		897,674		$	6	$	2		4.37		57,529
Exercised		(19,060	)		6		—		—		821
Outstanding at March 31, 2022		878,614		$	6	$	2		4.13	$	40,860
Exercisable at March 31, 2022		878,614			6		—		4.13		40,860
Options vested and expected to vest		878,614			6		—		4.13		40,860