| Schedule of Cash, Cash Equivalents and Short-term Investments [Table Text Block] |
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Balance
Sheet Classifications
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Cost
Basis
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Unrealized
Gain
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Unrealized
(Loss)
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Recorded
Basis
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Cash
and Cash Equivalents
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Short-term
Investments
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Cash
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$
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514,815
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$
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—
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$
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—
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$
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514,815
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$
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514,815
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$
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—
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Money
market mutual funds
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122,231
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—
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—
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122,231
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122,231
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—
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Certificates
of deposit
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205,611
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—
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—
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205,611
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—
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205,611
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Available-for-sale
securities:
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Bond
mutual funds
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20,000
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36
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—
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20,036
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—
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20,036
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Corporate
bonds
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12,095
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5
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(144
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)
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11,956
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—
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11,956
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Trading
securities:
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Equity
investments
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4,998
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—
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(7
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)
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4,991
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—
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4,991
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Total
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$
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879,750
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$
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41
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$
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(151
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$
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879,640
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$
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637,046
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$
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242,594
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Cost
Basis
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Unrealized
Gain
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Unrealized
(Loss)
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Recorded
Basis
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Cash
and Cash Equivalents
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Short-term
Investments
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Cash
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$
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653,979
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$
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—
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$
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—
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$
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653,979
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$
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653,979
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$
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—
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Money
market mutual funds
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17,350
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—
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—
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17,350
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17,350
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—
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Certificates
of deposit
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211,910
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—
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—
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211,910
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2,751
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209,159
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Available-for-sale
securities:
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Corporate
bonds
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17,853
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40
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(116
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17,777
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—
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17,777
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Total
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$
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901,092
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$
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40
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$
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(116
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$
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901,016
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$
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674,080
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$
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226,936
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