CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash Flows From Operating Activities:
Net Loss	$ (37,880)	$ (40,431)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Depreciation and Amortization	3,174	3,713
Amortization and Premium of Marketable Securities, Net	(422)	(980)
(Gain) Loss on Sale or Disposal of Assets	(29)	7
Intangible Asset Impairment	3,500
Other Asset Impairment		1,800
Gain on Fair Value Remeasurement of Contingent Consideration	(4,236)	(1,612)
Non-Cash Income Tax Benefit	(228)
Stock-Based Compensation Expense	2,658	3,864
Changes in Operating Assets and Liabilities:
Accounts and Other Receivables	177	2,435
Prepaid and Other Current Assets	(1,280)	208
Accounts Payable and Accrued Expenses	864	(884)
Other Liabilities	(1,491)	(3,535)
Net Cash Used in Operating Activities	(35,193)	(35,415)
Cash Flows From Investing Activities:
Sales and Maturities of Marketable Securities	55,600	91,473
Purchases of Marketable Securities	(183,394)	(77,011)
Acquisition of Property and Equipment	(1,305)	(626)
Proceeds from Sale or Disposal of Assets	29	20
Net Cash (Used in) Provided by Investing Activities	(129,070)	13,856
Cash Flows From Financing Activities:
Net Proceeds from Stock Issuances	170,964	13,826
Proceeds from Issuance of Stock from Employee Benefit Plans	218	9
Issuance of Term Loan	2,962
Payment of Term Loan	(2,962)
Net Cash Provided by Financing Activities	171,182	13,835
Net Increase (Decrease) in Cash and Cash Equivalents	6,919	(7,724)
Cash and Cash Equivalents at Beginning of Period	11,232	24,310
Cash and Cash Equivalents at End of Period	18,151	$ 16,586
Non-cash Investing Activities
Accrued construction in progress	$ 63