Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016		Jun. 30, 2015
Operating activities
Net loss	$ (122,313)		$ (105,242)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	926		629
Amortization of premium on investment securities	759		1,803
Stock-based compensation expense	14,691		9,931
Gain on retirement of equipment			(11)
Changes in operating assets and liabilities:
Receivables from collaborators			57
Prepaid research and development	(5,502)		(11,185)
Prepaid expenses and other current assets	(2,204)		965
Prepaid and other long-term assets	(4,025)		1,702
Accounts payable	(5,443)		(1,341)
Accrued compensation and employee benefits	(824)		(538)
Accrued research and development	(3,688)		9,718
Accrued and other liabilities	777		808
Deferred revenue	22,011		(4,744)
Other long-term liabilities	(371)		1,533
Net cash used in operating activities	(105,206)		(95,915)
Investing activities
Purchases of property and equipment	(1,803)		(2,555)
Decrease in restricted cash (Development Partner)	196
Proceeds from sales of equipment			11
Purchases of investments	(155,436)		(167,652)
Proceeds from maturities of investments	214,378		162,099
Net cash provided by (used in) investing activities	57,335		(8,097)
Financing activities
Proceeds from public offering of common stock, net of underwriters discount			108,772
Payment of public offering cost	(242)		(358)
Proceeds from issuance of common stock pursuant to equity award plans	972		6,995
Net cash provided by financing activities	730		115,409
Net (decrease) increase in cash and cash equivalents	(47,141)		11,397
Cash and cash equivalents at beginning of period	186,488	[1]	57,514
Cash and cash equivalents at end of period	$ 139,347	[1]	$ 68,911

[1] Amounts include the assets and liabilities of our Development Partner a consolidated variable interest entity (“VIE”). Portola's interests and obligations with respect to the VIE's assets and liabilities are limited to those accorded to Portola in its agreement with the VIE. See Note 7, “Asset Acquisition and License Agreements,” to these condensed consolidated financial statements.