CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 100,488	$ 161,120
Short-term investments	134,005	219,028
Accounts receivable	5,172
Inventory	757
Restricted cash	461	1,411
Prepaid expenses and other current assets	28,700	20,136
Total current assets	269,583	401,695
Property and equipment, net	21,837	17,055
Restricted cash	2,092	2,076
Long-term investments	9,975	117,963
Intangible assets, net	141,545
Goodwill	44,406
Other assets	1,315	1,837
Total assets	490,753	540,626
Current liabilities:
Accounts payable	8,886	5,364
Accrued liabilities	61,427	54,554
Deferred rent—current portion	701	341
Total current liabilities	71,014	60,259
Deferred tax liabilities	31,166
Other liabilities	5,119	6,393
Total liabilities	107,299	66,652
Commitments and contingencies (Note 12)
Stockholders’ equity:
Preferred stock, par value of $0.001 per share—25,000,000 shares authorized; nil outstanding as of December 31, 2017 and 2016
Common stock, par value of $0.001 per share—250,000,000 shares authorized; 44,167,071 and 41,240,230 shares issued and outstanding as of December 31, 2017 and 2016, respectively	44	41
Additional paid-in capital	1,221,762	1,003,561
Accumulated other comprehensive income (loss)	(5,680)	905
Accumulated deficit	(832,672)	(530,533)
Total stockholders’ equity	383,454	473,974
Total liabilities and stockholders’ equity	$ 490,753	$ 540,626

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.