Cash, Cash Equivalents and Marketable Securities

The Company's investments in marketable debt securities, which consist of U.S. Treasury bills and commercial paper, are classified and accounted for as available-for-sale. The Company classifies its marketable debt securities as either short-term or long-term based on each instrument's underlying contractual maturity date. Unrealized gains and losses on marketable debt securities classified as available-for-sale are recognized in Accumulated other comprehensive income in the Condensed Consolidated Balance Sheets until realized.

The Company's cash, cash equivalents, and marketable securities by significant investment category are as follows:



	Fair Value								Balance Sheet Classification
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Marketable Securities
Balance at September 30, 2019
Cash									$	114,467	$	—

Level 1⁽¹⁾:
Money market funds	15,595		—		—		15,595		15,595		—
U.S. Treasury securities	82,386		12		—		82,398		46,310		36,088
Total Level 1	97,981		12		—		97,993		61,905		36,088

Level 2⁽²⁾:
Commercial paper	6,478		—		—		6,478		—		6,478

Total	$	104,459	$	12	$	—	$	104,471	$	176,372	$	42,566



	Fair Value								Balance Sheet Classification
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Marketable Securities
Balance at December 31, 2018
Cash									$	279,829	$	—

Level 1⁽¹⁾:
Money market funds	77		—		—		77		77		—

Total	$	77	$	—	$	—	$	77	$	279,906	$	—


(1)	Level 1 – Quoted prices in active markets for identical assets and liabilities.


(2)	Level 2 – Quoted prices in active markets for similar assets and liabilities, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.

Investments, Assets Designated for Retirement and Pension Plans and Associated Liabilities

The Company has a U.S. non-qualified deferred compensation plan that consists primarily of U.S. marketable securities and mutual funds. The aggregate cost basis for these investments was $16.5 million and $14.6 million as of September 30, 2019 and December 31, 2018, respectively.

The Company also maintains a pension plan for certain current and former employees in Germany. The pensions are individually fixed Euro amounts that vary depending on the function and the eligible years of service of the employee. The Company’s investment strategy is to support its pension obligations through reinsurance contracts. The BaFin—German Federal Financial Supervisory Authority—supervises the insurance companies and the reinsurance contracts. The BaFin requires each reinsurance contract to guarantee a fixed minimum return. The Company’s pension benefits are fully reinsured by group insurance contracts with ERGO Lebensversicherung AG, and the group insurance contracts are measured in accordance with BaFin guidelines (including mortality tables and discount rates) which are considered Level 2 inputs.

The following tables provide a summary of the fair value measurements for each major category of investments, assets designated for retirement and pension plans and associated liabilities measured at fair value on a recurring basis:



				Balance Sheet Classification
	Fair Value			Other Current Assets		Assets Designated for Retirement and Pension Plans		Investments		Other Current Liabilities			Retirement and Pension Plans
Balance at September 30, 2019

Level 1⁽¹⁾:
U.S. non-qualified deferred compensation plan	$	23,807		$	—	$	—	$	23,807	$	—		$	—

Level 2⁽²⁾:
Retirement and pension plan assets	15,571			1,282		14,289		—		—			—
Pension benefit obligation	(19,870		)	—		—		—		(1,282		)	(18,588		)
Total Level 2	(4,299		)	1,282		14,289		—		(1,282		)	(18,588		)

Total	$	19,508		$	1,282	$	14,289	$	23,807	$	(1,282	)	$	(18,588	)



				Balance Sheet Classification
	Fair Value			Other Current Assets		Assets Designated for Retirement and Pension Plans		Investments		Other Current Liabilities			Retirement and Pension Plans
Balance at December 31, 2018

Level 1⁽¹⁾:
U.S. non-qualified deferred compensation plan	$	19,442		$	—	$	—	$	19,442	$	—		$	—

Level 2⁽²⁾:
Retirement and pension plan assets	16,384			1,349		15,035		—		—			—
Pension benefit obligation	(20,908		)	—		—		—		(1,349		)	(19,559		)
Total Level 2	(4,524		)	1,349		15,035		—		(1,349		)	(19,559		)

Total	$	14,918		$	1,349	$	15,035	$	19,442	$	(1,349	)	$	(19,559	)


(1)	Level 1 – Quoted prices in active markets for identical assets and liabilities.


(2)	Level 2 – Quoted prices in active markets for similar assets and liabilities, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.

Contingent Consideration

The former owners of the Company's prior year acquisitions are eligible to receive additional cash consideration based on the attainment of certain operating metrics in the periods subsequent to acquisition. Contingent consideration is valued using significant inputs that are not observable in the market which are defined as Level 3 inputs pursuant to fair value measurement accounting. The Company determines the fair value of contingent consideration using discounted cash flow models.

The following table provides a reconciliation of the beginning and ending balance of Level 3 liabilities for the nine months ended September 30, 2019:



	Acquisition Earnout Accruals
Balance at December 31, 2018	$	(6,627	)
Acquisition earnouts (Note 8)	(5,862		)
Earnout accretion	(495		)
Earnout payments	3,009
Earnout adjustments	(1,135		)
Foreign currency translation	209
Balance at September 30, 2019	$	(10,901	)