Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2018

Assets and Liabilities Measured at Fair Value on a Recurring Basis

Assets and liabilities measured at fair value on a recurring basis are categorized in the tables below based upon the lowest level of significant input to the valuations:



	As of June 30, 2018
	Level 1		Level 2		Level 3
Assets:
Short-term investments (1)	$	10,998	$	—	$	—
Total	$	10,998	$	—	$	—
Liabilities:
Contingent consideration (2)	$	—	$	—	$	1,019
Total	$	—	$	—	$	1,019
	As of December 31, 2017
	Level 1		Level 2		Level 3
Assets:
Short-term investments (1)	$	10,997	$	—	$	—
Total	$	10,997	$	—	$	—
Liabilities:
Contingent consideration (2)	$	—	$	—	$	412
Total	$	—	$	—	$	412


(1)	Short-term investments in the accompanying consolidated balance sheets are U.S. Treasury Bills. The fair values of these assets are based on Level 1 inputs in the fair value hierarchy.

(2)

Contingent consideration liability represents arrangements to pay the former owners of certain companies we acquired. The remaining undiscounted maximum payment under the arrangements is $1.1 million. We did not pay any amounts as part of these arrangements during the six months ended June 30, 2018. The change in the fair value of the contingent consideration from December 31, 2017 to June 30, 2018 is primarily related to our acquisition of Laser Control Systems Limited on March 9, 2018. See Note 17 – Business Combinations for further information regarding that acquisition.