Cash and available-for-sale securities are all current unless mentioned otherwise and consisted of the following as of September 30, 2017 and December 31, 2016 (in thousands):

	As of September 30, 2017
	Cost		Gross unrealized Gain		Gross unrealized Loss			Fair Value
Cash balances	$	64,133	$	—	$	—		$	64,133
Corporate debt securities, current portion	192,851		5		(75		)	192,781
Corporate debt securities, non-current portion	15,121		—		(12		)	15,109
Commercial paper	123,880		11		(10		)	123,881
Asset backed securities	30,346		—		(20		)	30,326
Money market	350		—		—			350
Certificate of deposit	50		—		—			50

	$	426,731	$	16	$	(117	)	$	426,630

Included in cash and cash equivalents	$	64,133	$	—	$	—		$	64,133
Included in marketable securities	362,598		16		(117		)	362,497

Total cash and marketable securities	$	426,731	16		$	(117	)	$	426,630

	As of December 31, 2016
	Cost		Unrealized Gain		Unrealized Loss			Fair Value
Cash balances	$	187,026	$	—	$	—		$	187,026
Corporate debt securities, current portion	74,564		2		(31		)	74,535
Commercial paper	68,258		132		—			68,390
Money market	350		—		—			350
Certificate of deposit	50		—		—			50

	$	330,248	$	134	$	(31	)	$	330,351

Included in cash and cash equivalents	$	187,026	$	—	$	—		$	187,026
Included in marketable securities	143,222		134		(31		)	143,325

Total cash and marketable securities	$	330,248	134		$	(31	)	$	330,351