Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (5,213)	$ (7,949)
Adjustments to reconcile net loss to net cash provided by (used for) operating activities:
Depreciation and amortization	3,670	3,675
Amortization of debt issuance costs and discounts	(995)	(1,050)
Amortization of discount or premium on available-for-sale securities		(116)
Share-based compensation expense	338	468
Changes in assets and liabilities:
Accounts receivable	(2,807)	1,054
Inventories	(2,034)	1,186
Prepaid expenses and other assets	1,999	1,004
Accounts payable	3,289	(5,306)
Accrued and other liabilities	2,114	389
Deferred revenue	(247)	(295)
Net cash provided by (used for) operating activities	114	(6,940)
Investing activities:
Fixed asset purchases		(21)
Purchases of available-for-sale securities		(13,876)
Proceeds from maturity of available-for-sale securities		12,885
Proceeds from sales of available-for-sale securities		562
Net cash used for investing activities		(450)
Financing activities:
Principal payments of financing leases	(52)
Net cash used for financing activities	(52)
Effect of exchange rates on cash and cash equivalents	143
Net increase (decrease) in cash and cash equivalents	205	(7,390)
Cash and cash equivalents:
Beginning of year	32,649	30,411
End of year	$ 32,854	$ 23,021