Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net loss	$ (30,794)	$ (25,237)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,172	1,224
Amortization of operating lease right-of-use assets	697
Stock-based compensation expense	3,310	5,279
Change in fair value of derivative instrument	361	(359)
Loss on disposal of property and equipment	(3)
Impairment of property and equipment		173
Non-cash interest expense	1,154	1,127
Deferred rent		(106)
Changes in operating assets and liabilities:
Accounts receivable	607	(1,126)
Prepaid expenses and other assets	627	(94)
Inventories	(882)	(12)
Accounts payable	2,017	524
Accrued expenses and other liabilities	1,211	(1,154)
Deferred revenue	(55)	(595)
Operating lease liabilities	(1,129)
Net cash used in operating activities	(21,707)	(20,356)
Cash flows from investing activities
Purchases and manufacture of property and equipment	(444)	(599)
Net cash used in investing activities	(444)	(599)
Cash flows from financing activities
Proceeds from issuance of common stock and stock option exercises, net	330	1,123
Proceeds from issuance of common stock in public offering, net of offering costs		49,379
Principal repayments of finance leases	(562)	(716)
Net cash (used in) provided by financing activities	(232)	49,786
Net (decrease) increase in cash, cash equivalents and restricted cash	(22,383)	28,831
Cash, cash equivalents and restricted cash at beginning of period	50,985	42,059
Cash, cash equivalents and restricted cash at end of period	28,602	70,890
Supplemental disclosures of cash flow information
Cash paid for interest	2,267	1,930
Supplemental disclosures of noncash activities
Transfer of T2 owned instruments and components to (from) inventory	(459)	802
Incremental fair value of warrant modification	147
Right-of-use assets obtained in exchange for new operating lease liabilities	4,805
Purchases of property and equipment included in accounts payable and accrued expenses	$ 193	$ 101