CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Statement of Cash Flows [Abstract]
Net loss	$ (10,375)	$ (14,273)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	662	510
Provision for inventory obsolescence	427	36
Loss on disposal of property and equipment	0	19
Stock based compensation	3,209	2,594
Net, non cash lease expense	0	2
Unrealized gain on short term investments	0	(164)
Provision (benefit) for allowance for doubtful accounts	486	(238)
Changes in operating assets and liabilities:
Trade receivables	1,389	(2,397)
Income tax receivables, prepaid expenses and other assets	(7,793)	(1,202)
Inventories	(717)	(1,772)
Accounts payable	15	50
Accrued and other liabilities	(2,352)	1,611
Net cash used in operating activities	(15,049)	(15,224)
Cash flows from investing activities
Purchases of property and equipment	(193)	(1,076)
Purchases of marketable securities	0	(18,884)
Proceeds from maturities of marketable securities	0	80,726
Net cash (used in) provided by investing activities	(193)	60,766
Cash flows from financing activities
Proceeds from stock option exercises	97	154
Repayment of finance lease liabilities	(184)	(2)
Contributions from non-controlling interests	148	0
Net cash provided by financing activities	61	152
Effect of exchange rates on cash	(92)	(18)
Net change in cash and cash equivalents	(15,273)	45,676
Cash and cash equivalents, beginning of period	58,812	16,596
Cash and cash equivalents, end of period	43,539	62,272
Cash paid for:
Interest	39	0
Income taxes	54	248
Non cash activities:
Right-of-use assets capitalized and lease liabilities recognized upon adoption of Topic 842	0	212
Right-of-use assets capitalized and lease liabilities recognized upon lease remeasurement	0	207
Right-of-use assets capitalized and lease liabilities recognized upon execution of lease	150	662
Transfer of other assets to property and equipment	0	42
Transfer of inventory from property and equipment	$ 10	$ 264