Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 327,778	$ 340,678
Accounts receivable	7,466	10,471
Prepaid expenses and other current assets	2,476	3,681
Total current assets	337,720	354,830
Property and equipment, net	16,010	15,272
Other assets	5,815	6,133
Total Assets	359,545	376,235
Current Liabilities:
Accounts payable	1,916	2,172
Accrued expenses	6,605	7,999
Current portion of deferred revenue	17,062	21,188
Total current liabilities	25,583	31,359
Deferred revenue, net of current portion	38,332	44,111
Other long-term liabilities	131	168
Commitments and contingencies
Stockholders' Equity:
Common stock, $0.0001 par value; 120,000,000 shares authorized, 43,091,922 shares and 42,384,623 shares issued and outstanding, respectively	4	4
Additional paid-in capital	432,533	421,706
Accumulated deficit	(137,038)	(121,113)
Total stockholders' equity	295,499	300,597
Total Liabilities and Stockholders' Equity	$ 359,545	$ 376,235

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.