In fiscal year 2019, we completed a public offering of 3,565 shares of our Class A common stock at a public offering price of $29.50 per share. The offering resulted in net proceeds to us of $100,446, after deducting underwriting discounts and commissions and offering expenses. The net proceeds from the offering were and are to be used for general corporate purposes, including potential acquisitions or development of new operations or assets with the goal of complementing or expanding our business, working capital and capital expenditures.

In fiscal year 2019, we completed the unregistered sale of 59 shares of our Class A common stock at a price of $44.15 per share. The sale resulted in net proceeds to us of $2,619. The shares were previously held in escrow according to the terms of our acquisition of WSI and released to us for liquidation to offset costs associated with the environmental remediation of the WSI's Potsdam, New York site. We recorded a $2,619 reduction of goodwill in line with business combination standards in place at the time the shares held in escrow were issued. See Note 12, Commitments and Contingencies for additional disclosure.

The holders of the Class A common stock are entitled to one vote for each share held. The holders of the Class B common stock are entitled to ten votes for each share held, except for the election of one director, who is elected by the holders of the Class A common stock exclusively. The Class B common stock is convertible into Class A common stock on a share-for-share basis at the option of the shareholder.

2006 Stock Incentive Plan. In the fiscal year ended April 30, 2007, we adopted the 2006 Stock Incentive Plan (“2006 Plan”). The 2006 Plan was amended in the fiscal year ended April 30, 2010. The 2006 Plan terminated as of October 9, 2016 and as a result no additional awards may be made pursuant to the 2006 Plan. Outstanding shares which are not actually issued under the 2006 Plan because such awards expire or otherwise result in shares not being issued are reserved for issuance under the 2016 Plan.

2016 Incentive Plan. In fiscal year 2016, we adopted the 2016 Incentive Plan (“2016 Plan”). Under the 2016 Plan, we may grant awards up to an aggregate amount of shares equal to the sum of: (i) 2,250 shares of Class A common stock (subject to adjustment in the event of stock splits and other similar events), plus (ii) such additional number of shares of Class A common stock (up to 2,723 shares) as is equal to the sum of the number of shares of Class A common stock that remained available for grant under the 2006 Plan immediately prior to the expiration of the 2006 Plan and the number of shares of Class A common stock subject to awards granted under the 2006 Plan that expire or otherwise result in shares not being issued.

As of December 31, 2019, there were 1,361 Class A common stock equivalents available for future grant under the 2016 Plan, inclusive of additional Class A common stock equivalents that were previously issued under terminated plans and have become available for grant because such awards expired or otherwise resulted in shares not being issued.

Our equity awards granted consist of stock options, including market-based performance stock options, restricted stock, restricted stock units and performance stock units, including market-based performance stock units.

Stock options are granted at a price equal to the prevailing fair value of our Class A common stock at the date of grant. Generally, stock options granted have a term not to exceed ten years and vest over a one year to four year period from the date of grant.

The fair value of each stock option granted, with the exception of market-based performance stock option grants, is estimated using a Black-Scholes option-pricing model, which requires extensive use of accounting judgment and financial estimation, including estimates of the expected term stock option holders will retain their vested stock options before exercising them and the estimated volatility of our Class A common stock price over the expected term. The fair value of each market-based performance stock option granted is estimated using a Monte Carlo option-pricing model, which also requires extensive use of accounting judgment and financial estimation, including estimates of the expected term stock option holders will retain their vested stock options before exercising them and the estimated volatility of our Class A common stock price over the expected term, but also including estimates of share price appreciation of our Class A common stock as compared to the Russell 2000 Index over the requisite service period.

Restricted stock, restricted stock units and performance stock units are granted at a price equal to the fair value of our Class A common stock at the date of grant. The fair value of each market-based performance stock unit is estimated using a Monte Carlo pricing model, which requires extensive use of accounting judgment and financial estimation, including the estimated share price appreciation plus the value of dividends of our Class A common stock as compared to the Russell 2000 Index over the requisite service period.

Restricted stock granted to non-employee directors vest incrementally over a three year period beginning on the first anniversary of the date of grant. Restricted stock units granted to non-employee directors vest in full on the first anniversary of the grant date. Restricted stock units vest incrementally over an identified service period beginning on the grant date based on continued employment. Performance stock units and market-based performance stock units vest at a future date following the grant date and are based on the attainment of performance targets and market achievements.


	Stock Options	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2018	669	$	6.37
Granted	—	$	—
Exercised	(571)	$	5.88
Forfeited or expired	—	$	—

Outstanding, December 31, 2019	98	$	9.20	5.8	$	3,614
Exercisable, December 31, 2019	98	$	9.20	5.8	$	3,614

Our calculation of stock-based compensation expense associated with stock options granted, with the exception of market-based performance stock option grants which are valued using a Monte Carlo option-pricing model, was made using the Black-Scholes valuation model. We did not grant any new stock options in fiscal years 2019, 2018 or 2017.

Expected life is calculated based on the weighted average historical life of the vested stock options, giving consideration to vesting schedules and historical exercise patterns. Risk-free interest rate is based on the U.S. Treasury yield curve for the period of the expected life of the stock option. Expected volatility is calculated using the weekly historical volatility of our Class A common stock over the expected life, except in the case of market-based performance stock option where the daily historical volatility of our Class A common stock over the expected life is used.

The Black-Scholes valuation model and the Monte Carlo option-pricing model each require extensive use of accounting judgment and financial estimation. Application of alternative assumptions could produce significantly different estimates of the fair value of stock-based compensation and consequently, the related amounts recognized in the consolidated statements of operations.


	Restricted Stock, Restricted Stock Units, and Performance Stock Units (1)	Weighted Average Grant Price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding, December 31, 2018	686	$	15.56
Granted	166	$	37.24
Class A common stock vested	(449)	$	12.38
Forfeited or canceled	(10)	$	23.41
Outstanding, December 31, 2019	393	$	28.23	1.3	$	6,992
Unvested, December 31, 2019	579	$	29.69	1.4	$	9,458

(1)Market-based performance stock unit grants are included at 100%. Attainment of maximum performance targets and market achievements would result in the issuance of an additional 186 shares of Class A common stock currently included in unvested. The market-based performance stock unit grants that vested in fiscal year 2019 resulted in the issuance of 178 additional shares of Class A common stock.

As of December 31, 2019, total unrecognized stock-based compensation expense related to restricted stock units was $3,156, which will be recognized over a weighted average period of 1.2 years. Total unrecognized stock-based compensation expense related to performance stock units, assuming the attainment of maximum performance targets, was $6,051, which will be recognized over a weighted average period of 1.5 years.

The weighted average fair value of market-based performance stock units granted during fiscal year 2019 was $38.74 per award, which was calculated using a Monte Carlo pricing model assuming a risk free interest rate of 2.28% and an expected volatility of 30.9% assuming no expected dividend yield. Risk-free interest rate is based on the U.S. Treasury yield curve for the expected service period of the award. Expected volatility is calculated using the daily volatility of our Class A common stock over the expected service period of the award.

The Monte Carlo pricing model requires extensive use of accounting judgment and financial estimation. Application of alternative assumptions could produce significantly different estimates of the fair value of stock-based compensation and consequently, the related amounts recognized in the consolidated statements of operations.

Accumulated other comprehensive income (loss) is a component of stockholders' equity (deficit) included in the accompanying consolidated balance sheets and includes, as applicable, the effective portion of changes in the fair value of our cash flow hedges and the changes in fair value of our marketable securities.


	Marketable Securities		Interest Rate Swaps		Total
Balance as of December 31, 2016	$	(68)	$	—	$	(68)

Other comprehensive income (loss) before reclassifications	59		(143)		(84)
Amounts reclassified from accumulated other comprehensive income (loss)	—		421		421
Income tax expense related to items in other comprehensive income (loss)	27		(112)		(85)
Other comprehensive income, net	86		166		252
Balance as of December 31, 2017	18		166		184
Cumulative effect of new accounting principle	(18)		—		(18)
Other comprehensive loss before reclassifications	—		(1,837)		(1,837)
Amounts reclassified from accumulated other comprehensive loss	—		363		363

Other comprehensive loss	—		(1,474)		(1,474)
Balance as of December 31, 2018	—		(1,308)		(1,308)

Other comprehensive loss before reclassifications	—		(5,286)		(5,286)
Amounts reclassified from accumulated other comprehensive loss	—		553		553

Other comprehensive loss	—		(4,733)		(4,733)
Balance as of December 31, 2019	$	—	$	(6,041)	$	(6,041)


	Fiscal Year Ended December 31,
	2019		2018		2017
Details About Accumulated Other Comprehensive Income (Loss) Components	Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss)							Affected Line Item in the Consolidated Statements of Operations
Interest rate swaps	$	553	$	363	$	421	Interest expense
	553		363		421		Income (loss) before income taxes
	—		—		—		Benefit for income taxes
	$	553	$	363	$	421	Net income (loss)