Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net (loss) income	$ (40,506)	$ 470,868
Income from discontinued operations, net of tax	20,261	546,872
Loss from continuing operations	(60,767)	(76,004)
Adjustments to reconcile net loss to net cash used in operating activities
Non-cash interest expense	240	3,678
Purchased premiums and interest on marketable securities	(2)
Amortization and accretion on marketable securities	(651)
Loss on extinguishment of debt		25,326
Non-cash activity related to discontinued operations	(171)	17,282
Benefit from intra period tax allocation	(7,695)	(42,399)
Loss on disposal of property and equipment	167
Gain on sale of property and equipment		(439)
Depreciation and amortization expense	4,074	5,221
Stock-based compensation expense	3,050	12,788
Loss on equity method investment	3,123	849
Gain on deconsolidation of Silver Creek Pharmaceuticals, Inc.		(10,848)
Changes in operating assets and liabilities:
Accounts receivable	100	175
Prepaid expenses and other assets	(993)	(8,476)
Accounts payable, accrued expenses and other	(3,801)	(9,278)
Deferred rent	(2,262)	(2,021)
Net cash used in continuing operations for operating activities	(65,588)	(84,146)
Net cash used in discontinued operations for operating activities		(41,665)
Net cash used in operating activities	(65,588)	(125,811)
Cash flows from investing activities
Purchase of marketable securities	(103,055)
Proceeds from sales and maturities of marketable securities	52,500
Purchase of property and equipment	(118)	(915)
Proceeds on sale of property and equipment	75	1,094
Proceeds from sale of a discontinued operation	28,000	580,714
Net cash (used in) provided by continuing operations for investing activities	(22,598)	576,891
Cash flows from financing activities
Payment of debt extinguishment costs		(20,124)
Proceeds from exercise of options and warrants to purchase common stock		6,917
Proceeds from issuance of note payable, net of issuance costs	14,632
Repayment of debt		(229,662)
Payment of dividend		(140,000)
Other financing activities, net		(288)
Net cash provided by (used in) financing activities	14,632	(379,163)
Net (decrease) increase in cash, cash equivalents and restricted cash	(73,554)	71,917
Cash, cash equivalents and restricted cash, beginning of period	94,217	22,300
Cash, cash equivalents and restricted cash, end of period	20,663	94,217
Non-cash investing and financing activities
Purchases of property and equipment in accounts payable, accrued expenses and other		14
Supplemental disclosure of cash flows
Cash paid for income taxes	390	7,926
Cash paid for interest	586	30,966
Silver Creek Pharmaceuticals Inc [Member]
Adjustments to reconcile net loss to net cash used in operating activities
Loss on equity method investment	$ (3,100)	(800)
Gain on deconsolidation of Silver Creek Pharmaceuticals, Inc.		(10,848)
Cash flows from investing activities
Deconsolidation of Silver Creek Pharmaceuticals, Inc.		(4,002)
Cash flows from financing activities
Proceeds from issuance of preferred stock by Silver Creek Pharmaceuticals, Inc.		$ 3,994