Note 6 - Accrued Expenses and Other Long-Term Liabilities	12 Months Ended
Dec. 31, 2022
Notes To Financial Statements
ACCRUED EXPENSES AND OTHER LONG-TERM LIABILITIES	NOTE 6—ACCRUED EXPENSES AND OTHER LONG-TERM LIABILITIES Accrued expenses at December 31, 2022 consisted of accrued compensation and related benefits of $14.3 million, accrued purchases of $11.5 million, and various other liabilities. Accrued expenses at December 31, 2021 consisted of accrued compensation and related benefits of $5.6 million, accrued purchases of $2.8 million, and various other liabilities. The Company sponsors a defined contribution plan to assist eligible employees in providing for their future retirement needs. The Company’s contributions to the plan totaled $2.3 million, $1.2 million, and $0.9 million for the years ended December 31, 2022, 2021, and 2020, respectively. Other long-term liabilities were comprised primarily of worker’s compensation and occupational disease obligations discussed below. Workers’ Compensation and Occupational Disease Obligations We are self-insured for certain losses relating to workers’ compensation claims and occupational disease obligations under the Federal Mine Safety and Health Act of 1969, as amended. We purchase insurance coverage to reduce our exposure to significant levels of these claims. Self-insured losses are accrued based upon estimates of the aggregate liability for uninsured claims incurred as of the balance sheet date using current and historical claims experience and certain actuarial assumptions. The occupational disease benefit obligation represents the present value of the actuarially computed liabilities for such benefits over the employees’ applicable years of service. The occupational disease benefit liability was calculated using a discount rate of 5.60% and 3.26% at December 31, 2022 and 2021, respectively. As of December 31, 2022, the estimated aggregate liability for uninsured claims totaled $3.6 million, including $1.5 million of occupational disease obligations. Of the aggregate liability, $2.7 million was included in other long-term liabilities within the consolidated balance sheets. As of December 31, 2021, the estimated aggregate liability for uninsured claims totaled $3.9 million, including $1.4 million of occupational disease obligations. Of the aggregate liability, $2.4 million was included in other long-term liabilities within the consolidated balance sheets.

Note 6 - Accrued Expenses and Other Long-Term Liabilities

12 Months Ended

Dec. 31, 2022

ACCRUED EXPENSES AND OTHER LONG-TERM LIABILITIES

NOTE 6—ACCRUED EXPENSES AND OTHER LONG-TERM LIABILITIES

Accrued expenses at December 31, 2022 consisted of accrued compensation and related benefits of $14.3 million, accrued purchases of $11.5 million, and various other liabilities. Accrued expenses at December 31, 2021 consisted of accrued compensation and related benefits of $5.6 million, accrued purchases of $2.8 million, and various other liabilities. The Company sponsors a defined contribution plan to assist eligible employees in providing for their future retirement needs. The Company’s contributions to the plan totaled $2.3 million, $1.2 million, and $0.9 million for the years ended December 31, 2022, 2021, and 2020, respectively.

Other long-term liabilities were comprised primarily of worker’s compensation and occupational disease obligations discussed below.

Workers’ Compensation and Occupational Disease Obligations

We are self-insured for certain losses relating to workers’ compensation claims and occupational disease obligations under the Federal Mine Safety and Health Act of 1969, as amended. We purchase insurance coverage to reduce our exposure to significant levels of these claims. Self-insured losses are accrued based upon estimates of the aggregate liability for uninsured claims incurred as of the balance sheet date using current and historical claims experience and certain actuarial assumptions. The occupational disease benefit obligation represents the present value of the actuarially computed liabilities for such benefits over the employees’ applicable years of service. The occupational disease benefit liability was calculated using a discount rate of 5.60% and 3.26% at December 31, 2022 and 2021, respectively.

As of December 31, 2022, the estimated aggregate liability for uninsured claims totaled $3.6 million, including $1.5 million of occupational disease obligations. Of the aggregate liability, $2.7 million was included in other long-term liabilities within the consolidated balance sheets. As of December 31, 2021, the estimated aggregate liability for uninsured claims totaled $3.9 million, including $1.4 million of occupational disease obligations. Of the aggregate liability, $2.4 million was included in other long-term liabilities within the consolidated balance sheets.