4.	Balance Sheet Components

Cash and Cash Equivalents

Cash and cash equivalents consisted of the following (in thousands):

	March 31, 2016		December 31, 2015
Cash	$	96,198	$	75,685
Money market funds		44,761		77,639
Total cash and cash equivalents	$	140,959	$	153,324

At March 31, 2016, a total of $26.0 million of our cash and cash equivalents were held outside of the U.S. in our foreign subsidiaries to be used primarily for our China operations.

Investments

All investments are classified as available-for-sale. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s available-for-sale investments by major investments type are summarized in the tables below (in thousands):

	March 31, 2016
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
Corporate bonds	$	125,825	$	529	$	(75	)	$	126,279
Certificate of deposits		2,241		—		—			2,241
Bond and mutual funds		25,712		—		—			25,712
Equity investments		126		105		—			231
Total investments	$	153,904	$	634	$	(75	)	$	154,463

	December 31, 2015
	Amortized Cost		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Fair Value
Corporate bonds	$	126,522	$	54	$	(473	)	$	126,103
Certificate of deposits		8,217		—		(2	)		8,215
Bond and mutual funds		25,052		—		—			25,052
Equity investments		126		71		—			197
Total investments	$	159,917	$	125	$	(475	)	$	159,567

At March 31, 2016, all of the available-for-sale investments had contractual maturities within three years. The Company periodically reviews its available-for-sale investments for other-than-temporary impairment. The Company considers factors such as the duration, severity and the reason for the decline in value, the potential recovery period and our intent to sell. For debt securities, the Company also considers whether (i) it is more likely than not that the Company will be required to sell the debt securities before recovery of their amortized cost basis, and (ii) the amortized cost basis cannot be recovered as a result of credit losses. During the three months ended March 31, 2016 and 2015, the Company did not recognize any other-than-temporary impairment loss.

Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	March 31, 2016		December 31, 2015
Preclinical and clinical trial accruals	$	29,023	$	27,973
Payroll and related accruals		9,511		13,535
Professional services		1,338		1,662
Other		4,166		4,762
Total accrued liabilities	$	44,038	$	47,932