Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (11,716)	$ (1,917)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,972	945
Gain on disposal of property and equipment	0	(16)
Stock-based compensation	2,905	1,759
Amortization of debt issuance costs	0	8
Interest on end-of-term debt obligation	54	64
Write-down of excess supplies	1,088	0
Noncash lease expense	232	212
Revaluation of acquisition-related contingent consideration	(484)	0
Changes in operating assets and liabilities:
Accounts receivable	238	(3,447)
Supplies	(376)	(366)
Prepaid expenses and other current assets	(818)	(11)
Operating lease liability	(331)	(292)
Other assets	135	37
Accounts payable	5,450	1,726
Accrued liabilities	(3,650)	287
Net cash used in operating activities	(5,301)	(1,011)
Investing activities
Purchases of property and equipment	(665)	(765)
Proceeds from disposal of property and equipment	0	16
Net cash used in investing activities	(665)	(749)
Financing activities
Payment of long-term debt	0	(12,500)
Payment of finance lease liability	0	(75)
Payment of taxes on vested restricted stock units	(2,304)	(556)
Proceeds from the exercise of common stock options and employee stock purchases	2,085	4,737
Net cash used in financing activities	(219)	(8,394)
Net decrease in cash, cash equivalents and restricted cash	(6,185)	(10,154)
Cash, cash equivalents and restricted cash at beginning of period	159,920	78,598
Cash, cash equivalents and restricted cash at end of period	153,735	68,444
Supplementary cash flow information:
Purchases of property and equipment included in accounts payable and accrued liability	113	95
Interest paid on debt	1	228
Total cash, cash equivalents and restricted cash	$ 159,920	$ 68,444