Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Financial Assets Recognized at Fair Value

As of December 31, 2017 and 2016, the Company’s financial assets recognized at fair value consisted of the following:

	Fair Value as of December 31, 2017
	Total		Level 1		Level 2		Level 3
	(In thousands)
Cash equivalents	$	330,896	$	330,896	$	-	$	-
Total	$	330,896	$	330,896	$	-	$	-

	Fair Value as of December 31, 2016
	Total		Level 1		Level 2		Level 3
	(In thousands)
Cash equivalents	$	270,448	$	270,448	$	-	$	-
Total	$	270,448	$	270,448	$	-	$	-

Summary of Property and Equipment at Cost and Recognizes Depreciation and Amortization Using the Straight-Line Method Over Estimated Useful Lives

The Company records property and equipment at cost and recognizes depreciation and amortization using the straight-line method over the following estimated useful lives of the respective assets:

Asset Category		Useful Life
Laboratory equipment		5 years
Office furniture and equipment		5 years
Computer software		3 years
Computer equipment		3 years
Leasehold improvements		5 years or term of respective lease, if shorter