CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash Flows From Operating Activities:
Net Loss	$ (23,656)	$ (29,018)
Adjustments to Reconcile Net Loss to Net Cash Used in Operating Activities:
Depreciation and Amortization	2,313	2,505
Amortization and Premium of Marketable Securities, Net	(335)	(652)
(Gain) Loss on Sale or Disposal of Assets	(20)	7
Intangible Asset Impairment	3,500
Other Asset Impairment		1,800
(Gain) Loss on Fair Value Remeasurement of Contingent Consideration	(4,898)	502
Non-Cash Income Tax Benefit	(228)
Stock-Based Compensation Expense	1,408	3,157
Changes in Operating Assets and Liabilities:
Accounts and Other Receivables	686	1,992
Prepaid and Other Current Assets	(436)	(137)
Accounts Payable and Accrued Expenses	(254)	(1,598)
Other Liabilities	(1,412)	(2,833)
Net Cash Used in Operating Activities	(23,332)	(24,275)
Cash Flows From Investing Activities:
Sales and Maturities of Marketable Securities	47,000	67,386
Purchases of Marketable Securities	(132,439)	(58,565)
Acquisition of Property and Equipment	(1,145)	(484)
Proceeds from Sale or Disposal of Assets	20
Net Cash (Used in) Provided by Investing Activities	(86,564)	8,337
Cash Flows From Financing Activities:
Net Proceeds from Stock Issuances	166,667	11,363
Proceeds from Issuance of Stock from Employee Benefit Plans	24	9
Issuance of Term Loan	2,962
Payment of Term Loan	(2,962)
Net Cash Provided by Financing Activities	166,691	11,372
Net Increase (Decrease) in Cash and Cash Equivalents	56,795	(4,566)
Cash and Cash Equivalents at Beginning of Period	11,232	24,310
Cash and Cash Equivalents at End of Period	68,027	19,744
Non-cash Investing Activities
Accrued construction in progress	$ 22	$ 55