3. Balance Sheet Details

Short-Term Investments

Short-term investments consist of U.S. government agency and government sponsored enterprise obligations. The Company accounts for these short-term investments as required by FASB ASC Topic No. 320, Investments-Debt and Equity Securities. These debt and equity securities are not classified as either held-to-maturity securities or trading securities. As such, they are classified as available-for-sale securities. Available-for-sale securities are recorded at fair value, with unrealized gains or losses recorded as a separate component of accumulated other comprehensive income in stockholders’ equity until realized. Available-for-sale securities with contractual maturities of less than 12 months were as follows (in thousands):


	December 31, 2014							December 31, 2013
	Amortized cost basis		Gross unrealized loss			Fair value		Amortized cost basis		Gross unrealized loss			Fair value
Corporate bonds and notes	$	1,000	$	(1	)	$	999	$	919	$	(1	)	$	918
Government securities/money market		1,881		—			1,881		2,160		—			2,160

Total	$	2,881	$	(1	)	$	2,880	$	3,079	$	(1	)	$	3,078

There were no realized gains (losses) recognized in interest and other income for the years ended December 31, 2014 and 2013. There was a de minimis amount of realized gains recognized for the year ended December 31 2012.

Equipment and Improvements

Equipment and improvements consist of the following (in thousands):


	December 31,
	2014			2013
Computer hardware, software, and equipment	$	16,143		$	16,529
Leasehold improvements		5,170			5,317
Office furniture and fixtures		1,213			1,213

		22,526			23,059
Less accumulated depreciation and amortization		(18,253	)		(16,036	)

Equipment and improvements, net	$	4,273		$	7,023

Depreciation and amortization expense on equipment and improvements was $2.9 million, $4.0 million and $4.4 million for the years ended December 31, 2014, 2013 and 2012 respectively.

The Company recorded an impairment charge related to our restructuring against certain equipment and improvements in the amount of $1.0 million for the year ended December 31, 2013. See Note 2 above, “Restructuring.”

Other Assets

These are office rent deposits.

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):


	December 31,
	2014		2013
Salaries and benefits	$	2,779	$	3,651
Restructuring		912		1,978
Pennsylvania grant liability		1,000		1,000
Royalties and revenue sharing		835		803
Income taxes		160		176
Marketing expenses, rebates and other		66		126

Total accrued liabilities	$	5,752	$	7,734

Deferred Rent and Other Long Term Liabilities

Deferred rent and other long term liabilities consist of the following (in thousands):


	December 31,
	2014		2013
Deferred rent	$	1,643	$	1,986
Restructuring - beyond one year		1,977		1,394
Sublease deposits		23		—
Deferred revenue - long term		—		3

Total deferred rent and other long term liabilities	$	3,643	$	3,383