Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net loss	$ (31,685)	$ (50,528)
Adjustments to reconcile net loss to net cash used for operating activities:
Share-based compensation expense	6,711	9,402
Depreciation expense	1,130	992
Loss on disposal of equipment	15	132
Accretion of right-of-use lease asset	(302)
Non-cash interest expense	2,310	0
Changes in operating assets and liabilities:
Accounts receivable, net	(618)	0
Inventory, net	43	(820)
Prepaid expenses and other current assets	(28)	(3,179)
Accounts payable	(5,531)	(4,163)
Accrued expenses	742	3,577
Accrued payroll and related expenses	(5,473)	(1,951)
Deferred rent	0	688
Net cash used for operating activities	(32,686)	(45,850)
Investing activities
Purchase of property and equipment	(184)	(994)
Net cash used for investing activities	(184)	(994)
Financing activities
Proceeds from the issuance of common stock under ESPP	283	0
Net proceeds from the issuance of common stock	0	109,809
Net proceeds from the exercise of stock options for common stock	0	528
Net cash provided by financing activities	283	110,337
Net (decrease) increase in cash, cash equivalents and restricted cash	(32,587)	63,493
Cash, cash equivalents and restricted cash at beginning of period	173,513	91,824
Cash, cash equivalents and restricted cash at end of period	140,926	155,317
Supplemental disclosure of non-cash investing and financing activities:
Noncash Or Part Noncash Transaction, Conversion Of Preferred Stock, Common Stock	2,737	0
Initial recognition of right-of-use lease asset	16,798
Reconciliation of cash, cash equivalents and restricted cash to the condensed consolidated balance sheets
Total cash, cash equivalents and restricted cash	$ 173,513	$ 91,824