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, 2015							December 31, 2014
	Amortized cost basis		Gross unrealized loss			Fair value		Amortized cost basis		Gross unrealized loss			Fair value
Corporate bonds and notes	$	—	$	—		$	—	$	1,000	$	(1	)	$	999
Government securities/money market		4,080		(2	)		4,078		1,881		—			1,881

Total	$	4,080	$	(2	)	$	4,078	$	2,881	$	(1	)	$	2,880

There were no realized gains (losses) recognized in interest and other income for the years ended December 31, 2015, 2014, and 2013.

Equipment and Improvements

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


	December 31,
	2015			2014
Computer hardware, software, and equipment	$	16,288		$	16,143
Leasehold improvements		5,170			5,170
Office furniture and fixtures		1,214			1,213

		22,672			22,526
Less accumulated depreciation and amortization		(20,180	)		(18,253	)

Equipment and improvements, net	$	2,492		$	4,273

Depreciation and amortization expense on equipment and improvements was $1.9 million, $2.9 million and $4.0 million for the years ended December 31, 2015, 2014, and 2013 respectively.

Other Assets

These are office rent deposits.

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):


	December 31,
	2015		2014
Salaries and benefits	$	2,723	$	2,779
Restructuring		442		912
Pennsylvania grant liability		1,000		1,000
Royalties and revenue sharing		643		835
Income taxes		205		160
Marketing expenses, rebates, and other		51		66

Total accrued liabilities	$	5,064	$	5,752

Deferred Rent and Other Long-Term Liabilities

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


	December 31,
	2015		2014
Deferred rent	$	1,402	$	1,643
Restructuring - beyond one year		1,767		1,977
Sublease deposits		66		23

Total deferred rent and other long-term liabilities	$	3,235	$	3,643