Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (8,591)	$ (31,685)
Adjustments to reconcile net loss to net cash used for operating activities:
Share-based compensation expense	2,407	6,782
Share-based compensation expense		6,711
Depreciation and amortization expense	1,060	1,130
Loss on disposal of equipment	148	15
Non-cash interest expense	1,682	2,310
Non-cash rent expense	345	316
Changes in operating assets and liabilities:
Accounts receivable, net	(592)	(618)
Inventory, net	251	43
Prepaid expenses and other current assets	1,084	(28)
Accounts payable	(2,282)	(5,531)
Accrued expenses	(2,404)	742
Accrued payroll and related expenses	(4,683)	(5,473)
Lease liability	(674)	(618)
Net cash used for operating activities	(12,249)	(32,686)
Investing activities
Proceeds from the sale of property and equipment	1,143	0
Purchase of property and equipment	0	(184)
Net cash provided by (used for) investing activities	1,143	(184)
Financing activities
Proceeds from the issuance of common stock under ESPP		283
Net proceeds from issuance of common stock under 2013 Equity Plan		0
Net cash provided by financing activities	505	283
Net decrease in cash and restricted cash	(10,601)	(32,587)
Cash and restricted cash at beginning of period	88,729	173,513
Cash and restricted cash at end of period	78,128	140,926
Supplemental disclosure of non-cash investing and financing activities:
Conversion of Series F Convertible Preferred Stock into common stock	0	2,737
Initial recognition of right-of-use lease asset	0	16,798
Reconciliation of cash and restricted cash to the condensed consolidated balance sheets
Total cash and restricted cash	$ 78,128	$ 140,926