Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS USED IN OPERATING ACTIVITIES:
Net loss	$ (108,278)	$ (180,239)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,785	2,005
Amortization of discount on marketable securities, net	(246)	(199)
Amortization of debt discount and debt issuance costs	11,638	10,174
Impairment loss on operating lease right of use assets	339
Stock-based compensation	16,911	22,270
(Gain)/Loss on property and equipment disposals	201	0
Changes in operating assets and liabilities:
Inventory	1,299	(1,180)
Accounts receivable, net	(4,770)	(8,467)
Prepaid expenses	(1,359)	(4,922)
Other current assets	344	998
Operating lease right of use assets	1,507
Other long-term assets	132	210
Accounts payable	382	2,379
Accrued expenses and other current liabilities	6,879	(7,455)
Lease liability, operating leases	(1,704)
Other non-current liabilities	(71)	(71)
Net cash used in operating activities	(75,011)	(164,497)
CASH FLOWS PROVIDED BY INVESTING ACTIVITIES:
Purchases of property and equipment	0	(70)
Purchases of marketable securities	(36,589)	(499)
Sales and maturities of marketable securities	135,500	97,501
Net cash provided by (used in) investing activities	98,911	96,932
CASH FLOWS PROVIDED BY FINANCING ACTIVITIES:
Proceeds from exercise of stock options and warrant exercises	3,869	8,953
Proceeds from issuance of shares under employee stock purchase plan	1,840	2,565
Net cash provided by financing activities	5,709	11,518
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	29,609	(56,047)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF YEAR	59,881	118,619
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD	89,490	62,572
SUPPLEMENTAL DISCLOSURES:
Cash paid for interest	9,150	9,582
Cash paid for income taxes	0	22
Property and equipment purchases in accrued expenses at period end	0	$ 298
Right of use assets obtained in exchange for operating lease liability	$ 8,289