Cash and Investments

12 Months Ended

Dec. 31, 2015

Cash And Cash Equivalents [Abstract]

Cash and Investments

2. Cash and Investments

Cash, cash equivalents, short-term investments, and restricted cash consist of the following (in thousands):

	December 31,
	2015		2014
Cash	$	7,270	$	2,763
Cash equivalents—money market funds		1,500		—
Corporate commercial paper		5,404		9,362
Corporate debt securities		2,269		1,002
Total cash and cash equivalents		16,443		13,127
Short-term investments:
Corporate commercial paper		6,245		550
Treasury bonds		1,007		—
Corporate debt securities		6,028		12,713
Total short-term investments		13,280		13,263
Restricted cash equivalents—money market fund		250		250
Total cash, cash equivalents, short-term investments and    restricted cash equivalents	$	29,973	$	26,640

Gross unrealized gains and losses on our cash equivalents and short-term investments were not material as of December 31, 2015 and December 31, 2014. Our restricted cash balance at December 31, 2015 and 2014 relates to a letter of credit securing the lease of our corporate headquarters.