The Company and Summary of Significant Accounting Policies Narrative (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Sale of Stock [Line Items]
Revenue from Related Parties		$ 1,300	$ 400	$ 400
Accumulated deficit		(150,326)	(132,346)
Cash, Cash Equivalents, and Short-term Investments		229,900
Capitalized Computer Software, Additions		600	700	300
Impairment of Intangibles (Excl. Goodwill)		0	0	0
Goodwill, Impairment Loss		$ 0	0	$ 0
No of operating segments		2
Deferred Tax Assets, Valuation Allowance		$ 40,436	$ 40,070		$ 45,255	$ 42,339
Maximum
Sale of Stock [Line Items]
Product Liability, Warranty Period		3 years
Minimum
Sale of Stock [Line Items]
Product Liability, Warranty Period		1 year
Restricted stock units
Sale of Stock [Line Items]
Vesting percentage on 1st anniversary of grant (percent)		33.33%
Vesting percentage on 2nd anniversary of grant (percent)		33.33%
Vesting percentage on 3rd anniversary of grant (percent)		33.34%
Property and Equipment, excluding LHI and major ERP [Member]
Sale of Stock [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Not major ERP implementation [Member] | Software and Software Development Costs [Member]
Sale of Stock [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Major ERP implementation [Member] | Software and Software Development Costs [Member]
Sale of Stock [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Accounts Receivable [Member]
Sale of Stock [Line Items]
Concentration Risk, Percentage		19.30%	26.40%