Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 340,678	$ 273,064
Accounts receivable	10,471	6,454
Prepaid expenses and other current assets	3,681	1,788
Total current assets	354,830	281,306
Property and equipment, net	15,272	10,628
Other assets	6,133	7,035
Total Assets	376,235	298,969
Current Liabilities:
Accounts payable	2,172	4,652
Accrued expenses	7,999	5,900
Current portion of deferred revenue	21,188	20,178
Total current liabilities	31,359	30,730
Deferred revenue, net of current portion	44,111	58,109
Other long-term liabilities	168	293
Commitments and contingencies (Note 6)
Stockholders’ Equity:
Common stock, $0.0001 par value; 120,000,000 shares authorized; 42,384,623 shares issued and outstanding and 36,018,540 shares issued and outstanding, respectively	4	4
Additional paid-in capital	421,706	263,403
Accumulated deficit	(121,113)	(53,570)
Total stockholders’ equity	300,597	209,837
Total Liabilities and Stockholders’ Equity	$ 376,235	$ 298,969

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).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
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.