Income Taxes	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Deferred Tax Assets Net deferred income tax assets at June 30, 2017, include capitalized research and development costs, research and development tax credits, non-qualified stock-based compensation expense, deferred warranty revenue, warranty and inventory reserves, accrued vacation, and other items, partially offset by accelerated depreciation expense and intangible amortization that is not tax deductible. The Company’s total net deferred tax assets at June 30, 2017 were $20.3 million. In preparing the Company’s condensed consolidated financial statements, management assesses the likelihood that its deferred tax assets will be realized from future taxable income. In evaluating the Company’s ability to recover its deferred income tax assets, management considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction by jurisdiction basis. A valuation allowance is established if it is determined that it is more likely than not that some portion or all of the net deferred tax assets will not be realized. Management exercises significant judgment in determining its provisions for income taxes, its deferred tax assets and liabilities, and its future taxable income for purposes of assessing its ability to utilize any future tax benefit from its deferred tax assets. Although management believes that its tax estimates are reasonable, the ultimate tax determination involves significant judgments that could become subject to audit by tax authorities in the ordinary course of business. As of each reporting date, management considers new evidence, both positive and negative, that could impact management’s view with regard to future realization of deferred tax assets. As of June 30, 2017, the Company continues to demonstrate three-year cumulative pre-tax income in the U.S. federal and Arizona tax jurisdictions; however, the Company's Arizona R&D Tax Credits start to expire in 2018 with a significant tranche with a gross value of $1.2 million expiring if not used by the end of 2019. It appears that that the Company’s long term investments, which impact short term profits, will likely result in some of the R&D credits expiring before they are utilized. Therefore, management has concluded that it is more likely than not that a portion of the Company’s deferred tax assets will not be realized and has established a valuation allowance. The Company has completed research and development (“R&D”) tax credit studies which identified approximately $15.6 million in tax credits for federal, Arizona and California income tax purposes related to the 2003 through 2017 tax years. Management has made the determination that it is more likely than not that the full benefit of the R&D tax credit will not be sustained on examination and recorded a liability for unrecognized tax benefits of $4.3 million as of June 30, 2017. In addition, management accrued approximately $0.1 million for estimated uncertain tax positions related to certain state income tax liabilities as of June 30, 2017. The Company does not expect a significant increase or decrease in the total amount of unrecognized tax benefits within 12 months. Should the total unrecognized tax benefit of $4.4 million be recognized, the Company’s effective tax rate would be favorably impacted. Approximately $1.6 million of the unrecognized tax benefit associated with research and development credits has been netted against the research and development credit deferred tax asset. Effective Tax Rate The Company’s overall effective tax rate for the six months ended June 30, 2017, after discrete period adjustments, was 15.0%. Before discrete adjustments, the tax rate was 42.2%, which is more than the statutory rate primarily due to the impact of non-deductible losses in certain foreign jurisdictions, state taxes and non-deductible expenses for items such as Subpart F income, meals and entertainment and lobbying fees, partially offset by the domestic production activities and research and development tax credit deductions. The effective tax rate was unfavorably impacted by foreign losses for which the Company is not expected to receive a tax benefit. This was offset by the favorable impact of a $1.4 million discrete tax benefit associated with windfalls related to stock-based compensation for restricted stock units that vested or stock options that were exercised during the six months ended June 30, 2017.

Income Taxes

Deferred Tax Assets

Net deferred income tax assets at June 30, 2017, include capitalized research and development costs, research and development tax credits, non-qualified stock-based compensation expense, deferred warranty revenue, warranty and inventory reserves, accrued vacation, and other items, partially offset by accelerated depreciation expense and intangible amortization that is not tax deductible. The Company’s total net deferred tax assets at June 30, 2017 were $20.3 million.

In preparing the Company’s condensed consolidated financial statements, management assesses the likelihood that its deferred tax assets will be realized from future taxable income. In evaluating the Company’s ability to recover its deferred income tax assets, management considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction by jurisdiction basis. A valuation allowance is established if it is determined that it is more likely than not that some portion or all of the net deferred tax assets will not be realized. Management exercises significant judgment in determining its provisions for income taxes, its deferred tax assets and liabilities, and its future taxable income for purposes of assessing its ability to utilize any future tax benefit from its deferred tax assets.

Although management believes that its tax estimates are reasonable, the ultimate tax determination involves significant judgments that could become subject to audit by tax authorities in the ordinary course of business. As of each reporting date, management considers new evidence, both positive and negative, that could impact management’s view with regard to future realization of deferred tax assets. As of June 30, 2017, the Company continues to demonstrate three-year cumulative pre-tax income in the U.S. federal and Arizona tax jurisdictions; however, the Company's Arizona R&D Tax Credits start to expire in 2018 with a significant tranche with a gross value of $1.2 million expiring if not used by the end of 2019. It appears that that the Company’s long term investments, which impact short term profits, will likely result in some of the R&D credits expiring before they are utilized. Therefore, management has concluded that it is more likely than not that a portion of the Company’s deferred tax assets will not be realized and has established a valuation allowance.

The Company has completed research and development (“R&D”) tax credit studies which identified approximately $15.6 million in tax credits for federal, Arizona and California income tax purposes related to the 2003 through 2017 tax years. Management has made the determination that it is more likely than not that the full benefit of the R&D tax credit will not be sustained on examination and recorded a liability for unrecognized tax benefits of $4.3 million as of June 30, 2017. In addition, management accrued approximately $0.1 million for estimated uncertain tax positions related to certain state income tax liabilities as of June 30, 2017. The Company does not expect a significant increase or decrease in the total amount of unrecognized tax benefits within 12 months. Should the total unrecognized tax benefit of $4.4 million be recognized, the Company’s effective tax rate would be favorably impacted. Approximately $1.6 million of the unrecognized tax benefit associated with research and development credits has been netted against the research and development credit deferred tax asset.

Effective Tax Rate

The Company’s overall effective tax rate for the six months ended June 30, 2017, after discrete period adjustments, was 15.0%. Before discrete adjustments, the tax rate was 42.2%, which is more than the statutory rate primarily due to the impact of non-deductible losses in certain foreign jurisdictions, state taxes and non-deductible expenses for items such as Subpart F income, meals and entertainment and lobbying fees, partially offset by the domestic production activities and research and development tax credit deductions. The effective tax rate was unfavorably impacted by foreign losses for which the Company is not expected to receive a tax benefit. This was offset by the favorable impact of a $1.4 million discrete tax benefit associated with windfalls related to stock-based compensation for restricted stock units that vested or stock options that were exercised during the six months ended June 30, 2017.