The Company and Summary of Significant Accounting Policies - Accounts Receivable and Allowance for Doubtful Accounts and Sales Returns (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
The Company and Summary of Significant Accounting Policies
Accounts receivable	$ 24,558,000	$ 19,031,000
Accrued liabilities	15,995,000	11,681,000
Allowance for Doubtful Accounts
The Company and Summary of Significant Accounting Policies
Valuation allowance balance	217,000	34,000
Increase/ (decrease) in allowance for doubtful accounts	183,000	(324,000)
Allowance for Sales Returns
The Company and Summary of Significant Accounting Policies
Valuation allowance balance	81,000	26,000
Allowance utilized	82,000	26,000
Additional reduction	$ 137,000	$ 5,000