Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Measurements

Schedule of financial assets and liabilities subject to fair value measurements

	As of December 31, 2017		Level 1		Level 2		Level 3
	(In thousands)
Assets:
Money market funds and cash equivalents	$	24,061		—	$	24,061		—
Marketable securities		99,139		—		99,139		—
	$	123,200		—	$	123,200		—
Liabilities:
Kolltan acquisition contingent consideration	$	43,400		—		—	$	43,400
	$	43,400		—		—	$	43,400

	As of December 31, 2016		Level 1		Level 2		Level 3
	(In thousands)
Assets:
Money market funds and cash equivalents	$	20,445		—	$	20,445		—
Marketable securities		147,315		—		147,315		—
	$	167,760		—	$	167,760		—
Liabilities:
Kolltan acquisition contingent consideration	$	44,200		—		—	$	44,200
	$	44,200		—		—	$	44,200

Schedule of the Company's contingent consideration liabilities measured at fair value using Level 3 inputs

        The following table reflects the activity for the Company's contingent consideration liabilities measured at fair value using Level 3 inputs for the year ended December 31, 2017 (in thousands):

	Other Liabilities: Contingent Consideration
Balance at December 31, 2016	$	44,200
Fair value adjustments included in operating expenses		(800	)
Balance at December 31, 2017	$	43,400