CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities:
Net Loss	$ (118,080)	$ (81,550)	$ (59,123)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Depreciation and Amortization	2,388	1,932	2,047
Amortization of Intangible Assets	1,013us-gaap_AmortizationOfIntangibleAssets	1,013us-gaap_AmortizationOfIntangibleAssets	1,090us-gaap_AmortizationOfIntangibleAssets
Amortization and Premium of Marketable Securities	95	(1,366)	(660)
Realized Gain on Sales and Maturities of Marketable Securities	(11)us-gaap_MarketableSecuritiesGainLoss		(6)us-gaap_MarketableSecuritiesGainLoss
Loss (Gain) on Sale or Disposal of Assets	6	(21)	(74)
Stock-Based Compensation Expense	6,852us-gaap_ShareBasedCompensation	4,548us-gaap_ShareBasedCompensation	2,298us-gaap_ShareBasedCompensation
Non Cash Expense	72	97	226
Changes in Operating Assets and Liabilities:
Accounts and Other Receivables	62	(445)	126
Prepaid and Other Current Assets	(2,026)	(706)	33
Other Assets	65	276	(95)
Accounts Payable and Accrued Expenses	1,450	7,236	3,762
Other Liabilities	6,577	1,317	594
Net Cash Used in Operating Activities	(101,537)	(67,669)	(49,782)
Cash Flows From Investing Activities:
Sales and Maturities of Marketable Securities	109,232	38,894	52,360
Purchases of Marketable Securities	(148,314)	(112,118)	(69,255)
Acquisition of Property and Equipment	(1,929)	(4,219)	(303)
Proceeds from Sale or Disposal of Assets		21	218
Net Cash Used in Investing Activities	(41,011)	(77,422)	(16,980)
Cash Flows From Financing Activities:
Net Proceeds from Stock Issuances		295,697	83,784
Proceeds from Issuance of Stock from Employee Benefit Plans	1,171us-gaap_ProceedsFromStockPlans	5,403us-gaap_ProceedsFromStockPlans
Payments of Term Loan		(11,029)us-gaap_RepaymentsOfSecuredDebt	(3,971)us-gaap_RepaymentsOfSecuredDebt
Payments of Other Liabilities		(472)us-gaap_RepaymentsOfOtherLongTermDebt	(55)us-gaap_RepaymentsOfOtherLongTermDebt
Net Cash Provided by Financing Activities	1,171	289,599	79,758
Effect of Exchange Rate Changes on Cash and Cash Equivalents	(5)	(3)	2
Net Increase (Decrease) in Cash and Cash Equivalents	(141,382)	144,505	12,998
Cash and Cash Equivalents at Beginning of Period	169,402	24,897	11,899
Cash and Cash Equivalents at End of Period	28,020	169,402	24,897
Supplemental Disclosure of Cash Flow Information
Cash Paid for Interest		1,209us-gaap_InterestPaid	1,384us-gaap_InterestPaid
Non-cash Investing Activities
Accrued construction in progress	$ 1,027

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.

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- Details

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