Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Stock-Based Compensation (Textual) [Abstract]
Stock-based compensation expense	$ 3,462	$ 4,159
Number of shares authorized (in shares)	4,800,000
Number of additional shares authorized (in shares)	1,800,000
Stock options
Stock-Based Compensation (Textual) [Abstract]
Stock-based compensation expense	$ 1,401	$ 1,076
Stock award, vesting period	4 years
Stock award, exercise period	5 years
Awards other than options, decrease in number of shares reserved for issuance (in shares)	2
Common stock, shares reserved for issuance (in shares)	14,215,000
Number of shares available for future grants (in shares)	1,184,000
Dividend yield	0.00%	0.00%
Weighted-average fair value (in dollars per share)	$ 2.88	$ 3.09
Stock options, total intrinsic value of options exercised	$ 269	$ 108
Unrecognized compensation expense	$ 3,446
Weighted-average period of recognition	2 years 7 months 17 days
Cash received under stock option plans for exercises	$ 880	286
Restricted stock
Stock-Based Compensation (Textual) [Abstract]
Stock-based compensation expense	$ 2,013	$ 3,023
Stock award, vesting period	4 years
Unrecognized compensation expense	$ 3,851
Weighted-average period of recognition	2 years 6 months 7 days
Granted (in shares)	317,000	322,000
Weighted-average grant-date fair value (in dollars per share)	$ 8.19	$ 9.67
Employee stock purchase plan
Stock-Based Compensation (Textual) [Abstract]
Stock-based compensation expense	$ 48	$ 60
Number of shares available for future grants (in shares)	847,000
Shares issued (in shares)	44,000	45,000
Employee stock purchase plan, discount percentage attributable to compensation expense	15.00%
Cash received under the employee stock purchase plan	$ 336	$ 414
Employee stock purchase plan \| Maximum
Stock-Based Compensation (Textual) [Abstract]
Employee election percentage of pre-tax compensation withheld to purchase Company's common stock shares	6.00%
ESPP Plan \| Stock options
Stock-Based Compensation (Textual) [Abstract]
Stock-based compensation expense	$ 3,414	$ 4,099
ESPP Plan \| Employee stock purchase plan
Stock-Based Compensation (Textual) [Abstract]
Number of shares authorized (in shares)	1,650,000
Percentage of Company's common stock share price	85.00%

Share-Based Compensation Arrangement By Share Based Payment Award, Award Exercise Period

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Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Awards, Pre-Tax Contibution Percentage Of Compensation

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Share-Based Compensation Arrangement By Share-Based Payment Award, Non-Option Equity Instrument, Discount Percentage Attributable to Compensation Expense

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Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Reduction Of Number of Shares Reserved For Issuance

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Stock based compensation.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cash inflow from issuance of shares under share-based payment arrangement. Excludes option exercised.

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Number of additional shares authorized for issuance under share-based payment arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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