Note 2 - Investments and Restricted Cash	6 Months Ended
Jun. 30, 2016
Notes to Financial Statements
Cash Restricted Cash And Investments [Text Block]	Note 2. Investments and Restricted Cash Investments Our current investments, which are classified as "available for sale" and consist of bonds having maturities of greater than 90 days, had a fair value and cost basis of $15.1 million at June 30, 2016. We held no such investments as of December 31, 2015. At June 30, 2016 and December 31, 2015, the fair value of our non-current investments was $4.5 million and $1.5 million, respectively. Our non-current investments consist of marketable equity securities which are carried at fair value, and are primarily classified as “available-for-sale.” The cost basis of our non-current investments was approximately $3.2 million and $4.0 million at June 30, 2016 and December 31, 2015, respectively. During the first quarters of 2016 and 2015, we recognized impairment charges against current earnings of $1.0 million and $2.8 million, respectively, as we determined the impairments to be other-than-temporary. Restricted Cash and Investments Various laws, permits, and covenants require that funds be in place for certain environmental and reclamation obligations and other potential liabilities. We had a current restricted cash balance of $3.9 million as of June 30, 2016 representing funds deposited in escrow to be applied towards a potential settlement of environmental matters for the South Dakota and Colorado Superfund sites related to CoCa Mines, Inc. (see Note 4 for more information). Our non-current restricted investments are used primarily for reclamation funding or for funding surety bonds, and were $1.0 million at each of June 30, 2016 and December 31, 2015. Non-current restricted investments primarily represent investments in money market funds and certificates of deposit.

Note 2. Investments and Restricted Cash

Investments

Our current investments, which are classified as "available for sale" and consist of bonds having maturities of greater than 90 days, had a fair value and cost basis of $15.1 million at June 30, 2016. We held no such investments as of December 31, 2015.

At June 30, 2016 and December 31, 2015, the fair value of our non-current investments was $4.5 million and $1.5 million, respectively. Our non-current investments consist of marketable equity securities which are carried at fair value, and are primarily classified as “available-for-sale.” The cost basis of our non-current investments was approximately $3.2 million and $4.0 million at June 30, 2016 and December 31, 2015, respectively. During the first quarters of 2016 and 2015, we recognized impairment charges against current earnings of $1.0 million and $2.8 million, respectively, as we determined the impairments to be other-than-temporary.

Restricted Cash and Investments

Various laws, permits, and covenants require that funds be in place for certain environmental and reclamation obligations and other potential liabilities. We had a current restricted cash balance of $3.9 million as of June 30, 2016 representing funds deposited in escrow to be applied towards a potential settlement of environmental matters for the South Dakota and Colorado Superfund sites related to CoCa Mines, Inc. (see

Note 4

for more information). Our non-current restricted investments are used primarily for reclamation funding or for funding surety bonds, and were $1.0 million at each of June 30, 2016 and December 31, 2015. Non-current restricted investments primarily represent investments in money market funds and certificates of deposit.