Aggregate number of common shares reserved for future issuance.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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- Definition

The increase or decrease in number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding, including vested options.

+ References

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- Definition

Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

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Purchase price of common stock expressed as a percentage of its fair value.

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

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Note 8 - Equity Award Plans (Details Textual) - shares shares in Thousands		3 Months Ended		9 Months Ended
	Jan. 02, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Feb. 28, 2013
Common Stock, Capital Shares Reserved for Future Issuance		2,468		2,468		2,185
The 2013 Employee Stock Purchase Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance							143
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum				1.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease), Total	57
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent				85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		100		100
Stock Issued During Period, Shares, Employee Stock Purchase Plans		31	15	31	15
The2013 Equity Incentive Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance							643
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Outstanding Stock Maximum				5.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Period Increase (Decrease), Total	286