Stockholders' Equity	12 Months Ended
Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Stockholders' Equity	During the year ended December 31, 2020, 0.1 million shares of common stock were issued as a result of the exercise of stock options. During the year ended December 31, 2019, no shares of common stock were issued as a result of the exercise of stock options. During the year ended December 31, 2020, 0.2 million shares of common stock were issued as a result of RSU releases. During the year ended December 31, 2019, 0.1 million shares of common stock were issued as a result of RSU releases. During the year ended December 31, 2020, 44,000 shares of common stock were issued under the ESPP. During the year ended December 30, 2019, 26,000 shares of common stock were issued under the ESPP. Stock Repurchase Program On April 27, 2005, our Board of Directors (“Board”) authorized the repurchase of up to 666,666 outstanding shares of our common stock. As of September 30, 2020, the maximum number of shares remaining that can be repurchased under this program was 602,467. No shares were repurchased during the year ended December 31, 2020. We do not intend to repurchase shares without further approval from the Board. 2019 Cash Dividend As a part of the board of directors’ ongoing capital allocation review, on December 6, 2019 the board of directors authorized and declared a special cash distribution of $1.00 per share on each outstanding share of our common stock. The record date for this distribution was December 17, 2019 and the payment date was December 26, 2019. Accordingly, we paid $19.1 million to shareholders on December 26, 2019. In connection with the special cash distribution of $1.00 per share, the exercise price on all outstanding options as of December 27, 2019 was reduced by $1.00 as permitted under the 2010 and 2014 Plans which includes an anti-dilution feature designed to equalize the fair value of options as a result of a transaction such as this special distribution. This adjustment did not affect the fair value, vesting conditions or classification of the outstanding options. Stockholder Rights Agreement and Tax Benefits Preservation Plan Our board adopted a Section 382 Tax Benefits Preservation Plan in an effort to diminish the risk that our ability to utilize net operating loss carryovers (collectively, the “NOLs”) to reduce potential future federal income tax obligations may become substantially limited. Our stockholders approved the Section 382 Tax Benefits Preservation Plan at our annual meeting of stockholders held on June 5, 2020. Under the Internal Revenue Code of 1986, as amended (the “Code”), and the regulations promulgated thereunder by the U.S. Treasury Department, these NOLs may be “carried forward” in certain circumstances to offset any current and future taxable income and thus reduce federal income tax liability, subject to certain requirements and restrictions. However, if we experience an “ownership change,” within the meaning of Section 382 of the Code (“Section 382”), our ability to utilize the NOLs may be substantially limited, and the timing of the usage of the NOLs could be substantially delayed, which could therefore significantly impair the value of those assets. Section 382 and the Treasury regulations thereunder make our commercial risk from a Section 382 limitation triggering event particularly acute given the relative size of current cash on hand to market capitalization. As applied to our current cash position and current market capitalization, if we were to experience an ownership change, it would be subject to Section 382’s “non-business asset” limitation, which would result in permanently losing all $145.6 million of our NOLs. The Section 382 Tax Benefits Preservation Plan is intended to act as a deterrent to any person or group acquiring beneficial ownership of 4.99% or more of the outstanding Common Stock without the approval of the board (such person, an “Acquiring Person”). A person who acquires, without the approval of the board, beneficial ownership (other than as a result of repurchases of stock by the Company, dividends or distributions by the Company or certain inadvertent actions by stockholders) of 4.99% or more of the outstanding common stock (including any ownership interest held by that person's Affiliates and Associates as defined under the Section 382 Tax Benefits Preservation Plan) could be subject to significant dilution. Stockholders who beneficially own 4.99% or more of the outstanding common stock prior to the first public announcement by the Company of the board’s adoption of the Section 382 Tax Benefits Preservation Plan will not trigger the Section 382 Tax Benefits Preservation Plan so long as they do not acquire beneficial ownership of additional shares of the Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock) at a time when they still beneficially own 4.99% or more of such stock. In addition, the board retains the sole discretion to exempt any person or group from the penalties imposed by the Section 382 Tax Benefits Preservation Plan. In the event that a person becomes an Acquiring Person, each holder of a Right, other than Rights that are or, under certain circumstances, were beneficially owned by the Acquiring Person (which will thereupon become void), will thereafter have the right to receive upon exercise of a Right and payment of the Purchase Price, and subject to the terms, provisions and conditions of the Section 382 Tax Benefits Preservation Plan, a number of shares of the Common Stock having a market value of two times the Purchase Price.

Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Stockholders' Equity Note [Abstract]

During the year ended December 31, 2020, 0.1 million shares of common stock were issued as a result of the exercise of stock options. During the year ended December 31, 2019, no shares of common stock were issued as a result of the exercise of stock options.

During the year ended December 31, 2020, 0.2 million shares of common stock were issued as a result of RSU releases. During the year ended December 31, 2019, 0.1 million shares of common stock were issued as a result of RSU releases.

During the year ended December 31, 2020, 44,000 shares of common stock were issued under the ESPP. During the year ended December 30, 2019, 26,000 shares of common stock were issued under the ESPP.

Stock Repurchase Program

On April 27, 2005, our Board of Directors (“Board”) authorized the repurchase of up to 666,666 outstanding shares of our common stock. As of September 30, 2020, the maximum number of shares remaining that can be repurchased under this program was 602,467. No shares were repurchased during the year ended December 31, 2020. We do not intend to repurchase shares without further approval from the Board.

2019 Cash Dividend

As a part of the board of directors’ ongoing capital allocation review, on December 6, 2019 the board of directors authorized and declared a special cash distribution of $1.00 per share on each outstanding share of our common stock. The record date for this distribution was December 17, 2019 and the payment date was December 26, 2019. Accordingly, we paid $19.1 million to shareholders on December 26, 2019. In connection with the special cash distribution of $1.00 per share, the exercise price on all outstanding options as of December 27, 2019 was reduced by $1.00 as permitted under the 2010 and 2014 Plans which includes an anti-dilution feature designed to equalize the fair value of options as a result of a transaction such as this special distribution. This adjustment did not affect the fair value, vesting conditions or classification of the outstanding options.

Stockholder Rights Agreement and Tax Benefits Preservation Plan

Our board adopted a Section 382 Tax Benefits Preservation Plan in an effort to diminish the risk that our ability to utilize net operating loss carryovers (collectively, the “NOLs”) to reduce potential future federal income tax obligations may become substantially limited. Our stockholders approved the Section 382 Tax Benefits Preservation Plan at our annual meeting of stockholders held on June 5, 2020. Under the Internal Revenue Code of 1986, as amended (the “Code”), and the regulations promulgated thereunder by the U.S. Treasury Department, these NOLs may be “carried forward” in certain circumstances to offset any current and future taxable income and thus reduce federal income tax liability, subject to certain requirements and restrictions. However, if we experience an “ownership change,” within the meaning of Section 382 of the Code (“Section 382”), our ability to utilize the NOLs may be substantially limited, and the timing of the usage of the NOLs could be substantially delayed, which could therefore significantly impair the value of those assets. Section 382 and the Treasury regulations thereunder make our commercial risk from a Section 382 limitation triggering event particularly acute given the relative size of current cash on hand to market capitalization. As applied to our current cash position and current market capitalization, if we were to experience an ownership change, it would be subject to Section 382’s “non-business asset” limitation, which would result in permanently losing all $145.6 million of our NOLs.

The Section 382 Tax Benefits Preservation Plan is intended to act as a deterrent to any person or group acquiring beneficial ownership of 4.99% or more of the outstanding Common Stock without the approval of the board (such person, an “Acquiring Person”). A person who acquires, without the approval of the board, beneficial ownership (other than as a result of repurchases of stock by the Company, dividends or distributions by the Company or certain inadvertent actions by stockholders) of 4.99% or more of the outstanding common stock (including any ownership interest held by that person's Affiliates and Associates as defined under the Section 382 Tax Benefits Preservation Plan) could be subject to significant dilution. Stockholders who beneficially own 4.99% or more of the outstanding common stock prior to the first public announcement by the Company of the board’s adoption of the Section 382 Tax Benefits Preservation Plan will not trigger the Section 382 Tax Benefits Preservation Plan so long as they do not acquire beneficial ownership of additional shares of the Common Stock (other than pursuant to a dividend or distribution paid or made by the Company on the outstanding shares of Common Stock or pursuant to a split or subdivision of the outstanding shares of Common Stock) at a time when they still beneficially own 4.99% or more of such stock. In addition, the board retains the sole discretion to exempt any person or group from the penalties imposed by the Section 382 Tax Benefits Preservation Plan.

In the event that a person becomes an Acquiring Person, each holder of a Right, other than Rights that are or, under certain circumstances, were beneficially owned by the Acquiring Person (which will thereupon become void), will thereafter have the right to receive upon exercise of a Right and payment of the Purchase Price, and subject to the terms, provisions and conditions of the Section 382 Tax Benefits Preservation Plan, a number of shares of the Common Stock having a market value of two times the Purchase Price.