Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 349,462	$ 75,105
Short-term investments	0	6,862
Accounts and notes receivable, net of allowance of $1,882 and $754 as of December 31, 2018 and 2017, respectively	130,579	56,064
Contract assets, net	13,960	0
Inventory	33,763	45,465
Prepaid expenses and other current assets	30,391	21,696
Total current assets	558,155	205,192
Property and equipment, net	37,893	31,172
Deferred income tax assets, net	19,347	15,755
Intangible assets, net	15,935	18,823
Goodwill	24,981	14,927
Long-term notes receivable, net of current portion	40,230	36,877
Other assets	22,999	15,366
Total assets	719,540	338,112
Current liabilities:
Accounts payable	15,164	8,592
Accrued liabilities	41,092	23,502
Contract with customer, liability, current	107,016	70,401
Current portion of business acquisition contingent consideration	0	1,693
Other current liabilities	37	89
Total current liabilities	166,011	107,950
Deferred revenue, net of current portion	74,417	54,881
Liability for unrecognized tax benefits	2,849	1,706
Long-term deferred compensation	3,235	3,859
Business acquisition contingent consideration, net of current portion	0	1,048
Other long-term liabilities	5,704	1,224
Total liabilities	252,216	170,668
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred stock, $0.00001 par value; 25,000,000 shares authorized; no shares issued and outstanding as of December 31, 2018 and 2017	0	0
Common stock, $0.00001 par value; 200,000,000 shares authorized; 58,810,637 and 52,969,869 shares issued and outstanding as of December 31, 2018 and 2017, respectively	1	1
Additional paid-in capital	453,400	201,672
Treasury stock at cost, 20,220,227 shares as of December 31, 2018 and 2017	(155,947)	(155,947)
Retained earnings	171,383	123,185
Accumulated other comprehensive loss	(1,513)	(1,467)
Total stockholders’ equity	467,324	167,444
Total liabilities and stockholders’ equity	719,540	338,112
Current portion of deferred revenue
Current liabilities:
Contract with customer, liability, current	107,016	70,401
Customer deposits
Current liabilities:
Contract with customer, liability, current	$ 2,702	$ 3,673

The aggregate of amounts due from customers or clients, within one year of the balance sheet date (or one operating cycle, if longer), for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date within one year of the balance sheet, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively.

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- Definition

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).