Notes Payable	12 Months Ended
Dec. 31, 2016
Line of Credit Facility [Abstract]
Notes Payable	NOTES PAYABLE In December 2004, we entered into a line of credit agreement with a brokerage firm. Under the terms of this agreement, we may borrow funds at a cost equal to the current federal funds rate plus 125 basis points (1.91% as of December 31, 2016). Certain of our cash, cash equivalents and short-term investments secure borrowings outstanding under this facility, but we are not restricted in the use of those assets. Funds are advanced to us under this facility based on pre-determined advance rates on the cash and securities held by us in this brokerage account. This agreement has no set expiration date and there are no loan covenants, other than the aforementioned collateral requirement which does not legally restrict the cash and securities. At each of the years ended December 31, 2016 and 2015, $1.5 million and $5.1 million was outstanding under this facility, with a related collateral requirement of approximately of $2.0 million and $6.8 million of our cash, cash equivalents and short-term investments.

Notes Payable

12 Months Ended

Dec. 31, 2016

NOTES PAYABLE

In December 2004, we entered into a line of credit agreement with a brokerage firm. Under the terms of this agreement, we may borrow funds at a cost equal to the current federal funds rate plus 125 basis points (1.91% as of December 31, 2016). Certain of our cash, cash equivalents and short-term investments secure borrowings outstanding under this facility, but we are not restricted in the use of those assets. Funds are advanced to us under this facility based on pre-determined advance rates on the cash and securities held by us in this brokerage account. This agreement has no set expiration date and there are no loan covenants, other than the aforementioned collateral requirement which does not legally restrict the cash and securities. At each of the years ended December 31, 2016 and 2015, $1.5 million and $5.1 million was outstanding under this facility, with a related collateral requirement of approximately of $2.0 million and $6.8 million of our cash, cash equivalents and short-term investments.