STATEMENTS OF CASH FLOWS DATA (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Operating Activities:
Issuance of common stock for 401(k) matching contributions		$ 313	$ 839
Reclassification between deposits and other current assets		190	219
Supplemental Investing Activities:
Net unrealized loss on marketable securities	$ (129)	$ (70)	$ (54)