Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 54,126	$ 35,944
Short-term investments	257,221	136,653
Accounts receivable, net	31,658	29,937
Inventories, net	41,411	31,278
Prepaid expenses and other current assets	6,694	9,277
Total current assets	391,110	243,089
Long-term investments	60,047	0
Fixed assets, net	107,046	101,016
Goodwill	55,197	46,737
Equity investments	14,146	0
Other assets	825	624
Total assets	628,371	391,466
Current liabilities:
Accounts payable	14,658	7,511
Accrued expenses	41,057	36,666
Convertible senior notes	324	0
Current portion of deferred revenue	102	595
Income taxes payable	76	66
Total current liabilities	56,217	44,838
Convertible senior notes	276,173	108,738
Other liabilities	16,498	18,914
Total liabilities	348,888	172,490
Commitments and contingencies
Stockholders’ equity:
Preferred stock, par value $0.001; 5,000,000 shares authorized, none issued and outstanding at December 31, 2017 and 2016	0	0
Common stock, par value $0.001 and 250,000,000 shares authorized; 40,668,877 shares issued and outstanding at December 31, 2017; 37,480,952 shares issued and outstanding at December 31, 2016	41	37
Additional paid-in capital	669,032	565,207
Accumulated deficit	(389,136)	(346,238)
Accumulated other comprehensive loss	(454)	(30)
Total stockholders’ equity	279,483	218,976
Total liabilities and stockholders’ equity	$ 628,371	$ 391,466

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.