CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows From Operating Activities:
Net Loss	$ (141,781)	$ (89,190)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Depreciation and Amortization	2,856	3,392
Amortization of Intangible Assets	224	672
Amortization and Premium of Marketable Securities, Net	(666)	(171)
Loss on Sale or Disposal of Assets	1,170	6
Goodwill Impairment	90,976
Intangible Asset Impairment	18,677	13,000
Gain on Fair Value Remeasurement of Contingent Consideration	(27,968)	(200)
Non-Cash Income Tax Benefit	(765)	(5,200)
Stock-Based Compensation Expense	6,329	9,728
Changes in Operating Assets and Liabilities:
Accounts and Other Receivables	(790)	(1,229)
Prepaid and Other Current Assets	1,545	525
Other Assets		132
Accounts Payable and Accrued Expenses	(9,246)	(10,888)
Other Liabilities	(366)	(987)
Net Cash Used in Operating Activities	(59,805)	(80,410)
Cash Flows From Investing Activities:
Sales and Maturities of Marketable Securities	178,335	183,683
Purchases of Marketable Securities	(151,558)	(122,235)
Acquisition of Property and Equipment	(651)	(1,598)
Proceeds from Sale or Disposal of Assets	342
Net Cash Provided by Investing Activities	26,468	59,850
Cash Flows From Financing Activities:
Net Proceeds from Stock Issuances	25,453	32,642
Proceeds from Issuance of Stock from Employee Benefit Plans	419	192
Net Cash Provided by Financing Activities	25,872	32,834
Net (Decrease) Increase in Cash and Cash Equivalents	(7,465)	12,274
Cash and Cash Equivalents at Beginning of Period	40,288	42,461
Cash and Cash Equivalents at End of Period	32,823	54,735
Non-cash Investing Activities
Accrued construction in progress	86	75
Non-cash Supplemental Disclosure
Shares issued to former Kolltan executive for settlement of severance	$ 65	$ 302