Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities
Net loss	$ (9,777)	$ (16,294)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	4,470	5,708
Change in lease-related performance liabilities	(957)	(851)
Stock-based compensation expense	18,886	17,822
Amortization of debt discount and issuance costs	5,333	4,912
Deferred income taxes	(2,056)	0
Non-cash lease expense	1,676	1,237
Other	608	(681)
Changes in operating assets and liabilities:
Accounts receivable	3,782	3,361
Other receivables	(119)	(2,187)
Inventories	(5,673)	(51)
Prepaid expenses and other assets	(1,186)	(1,295)
Deferred commissions	(847)	336
Accounts payable	(1,067)	(1,206)
Increase (Decrease) in Other Accrued Liabilities	1,632	(2,090)
Deferred revenue	(5,227)	(2,453)
Net cash used in operating activities	9,478	6,268
Cash flows from investing activities
Purchase of property and equipment	(2,890)	(2,807)
Business acquisitions, net of cash acquired	(24,218)	0
Purchase of short-term investments	(89,429)	(43,384)
Maturities of short-term investments	84,255	101,241
Sales of short-term investments	29,381	0
Net cash used in investing activities	(2,901)	55,050
Cash flows from financing activities
Cash from lease-related performance obligations	854	1,338
Payment for purchase of capped calls	(8,907)
Proceeds from issuance of common stock from the employee stock purchase plan	1,966	1,809
Proceeds from exercise of stock options	2,073	2,248
Tax withholdings paid on behalf of employees for net share settlement	(5,932)	(10,763)
Net cash provided by financing activities	(1,039)	(5,368)
Net increase in cash and cash equivalents	5,538	55,950
Cash and cash equivalents at beginning of period	25,704	34,276
Cash and cash equivalents at end of period	31,242
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable and accrued liabilities	$ 314	$ 931