(12) FAIR VALUE MEASUREMENTS

The Company measures certain financial assets and liabilities at fair value on a recurring basis. In addition to available-for-sale debt securities, debt and foreign currency derivatives, which are disclosed in Notes 6, 10 and 11, respectively, the following tables below present the classification within fair value hierarchy of financial assets and liabilities not disclosed elsewhere.

	Fair Value Measurements at June 30, 2018
	Quoted Price in Active Markets For Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
Other current assets:
NQDC Plan assets	$	—	$	1,018	$	—	$	1,018
Restricted investments ⁽¹⁾		—		7,721		—		7,721
Total other current assets		—		8,739		—		8,739
Other assets:
NQDC Plan assets		—		12,832		—		12,832
Restricted investments ⁽¹⁾		—		6,889		—		6,889
Strategic investments⁽²⁾		1,616		—		—		1,616
Total other assets		1,616		19,721		—		21,337
Total assets	$	1,616	$	28,460	$	—	$	30,076
Liabilities:
Current liabilities:
NQDC Plan liability	$	1,050	$	1,018	$	—	$	2,068
Contingent acquisition consideration		—		—		76,466		76,466
Total current liabilities		1,050		1,018		76,466		78,534
Other long-term liabilities:
NQDC Plan liability	$	18,588	$	12,832		—		31,420
Contingent acquisition consideration		—		—		57,674		57,674
Total other long-term liabilities		18,588		12,832		57,674		89,094
Total liabilities	$	19,638	$	13,850	$	134,140	$	167,628

	Fair Value Measurements at December 31, 2017
	Quoted Price in Active Markets For Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets:
Other current assets:
NQDC Plan assets	$	—	$	967	$	—	$	967
Restricted investments ⁽¹⁾		—		15,647		—		15,647
Total other current assets		—		16,614		—		16,614
Other assets:
NQDC Plan assets	—			11,859		—		11,859
Total other assets		—		11,859		—		11,859
Total assets	$	—	$	28,473	$	—	$	28,473
Liabilities:
Current liabilities:
NQDC Plan liability	$	1,356	$	967	$	—	$	2,323
Contingent acquisition consideration	—		—			53,648		53,648
Total current liabilities		1,356		967		53,648		55,971
Other long-term liabilities:
NQDC Plan liability		18,272		11,859	—			30,131
Contingent acquisition consideration	—		—			135,318		135,318
Total other long-term liabilities		18,272		11,859		135,318		165,449
Total liabilities	$	19,628	$	12,826	$	188,966	$	221,420

(1)	The restricted investments at June 30, 2018 and December 31, 2017 secure the Company’s irrevocable standby letters of credit obtained in connection with certain commercial agreements.

(2)	The Company has investments in marketable equity securities measured using quoted prices in an active market that are considered strategic investments and included in other assets on the Company’s Consolidated Balance Sheets.

There were no transfers between levels during the three and six months ended June 30, 2018.

The Company’s Level 2 instruments are valued using third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities, prepayment/default projections based on historical data and other observable inputs. The Company validates the prices provided by its third-party pricing services by understanding the models used, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming those securities traded in active markets.

Liabilities measured at fair value using Level 3 inputs consisted of contingent acquisition consideration and asset retirement obligations. The following tables represent a roll-forward of contingent acquisition consideration.

Contingent acquisition consideration at December 31, 2017	$	188,966
Changes in the fair value of other contingent acquisition consideration		8,284
Milestone payments to Ares Trading S.A. (Merck Serono)		(61,607	)
Foreign exchange remeasurement of Euro denominated contingent acquisition consideration		(1,503	)
Contingent acquisition consideration at June 30, 2018	$	134,140

Under certain of the Company’s lease agreements, the Company is contractually obligated to return leased space to its original condition upon termination of the lease agreement. The Company records an asset retirement obligation liability and a corresponding capital asset in an amount equal to the estimated fair value of the obligation, when estimable. In subsequent periods, for each such lease, the Company records interest expense to accrete the asset retirement obligation liability to full value and depreciates each capitalized asset retirement obligation asset, both over the term of the associated lease agreement. As of June 30, 2018 and December 31, 2017, the balance of the asset retirement obligation liability was $4.2 million at each period.

The Company acquired intangible assets as a result of various business acquisitions. The estimated fair value of these long-lived assets was measured using Level 3 inputs as of the acquisition date. Refer to Note 3 – Significant Accounting Policies in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 for details on valuation.