Balance Sheet Components

Investments

The Company's short-term and long-term investments as of December 31, 2015 are as follows (in thousands):



Short-term
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Agency securities	$	1,551	$	—	$	(2	)	$	1,549
U.S. Treasury	500		—		—			500
Corporate bonds	7,776		—		(13		)	7,763
Commercial paper	500		—		—			500
Certificates of deposit	2,555		—		—			2,555
Total	$	12,882	$	—	$	(15	)	$	12,867


Long-term
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Agency securities	$	499	$	—	$	(2	)	$	497
U.S. Treasury	—		—		—			—
Corporate bonds	878		—		(4		)	874
Certificates of deposit	2,119		—		—			2,119
Total	$	3,496	$	—	$	(6	)	$	3,490

The Company's short-term and long-term investments as of December 31, 2014 are as follows (in thousands):



Short-term
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Agency securities	$	5,240	$	1	$	(1	)	$	5,240
U.S. Treasury	1,003		1		—			1,004
Corporate bonds	7,778		2		(6		)	7,774
Commercial paper	1,349		—		—			1,349
Certificates of deposit	919		—		—			919
Total	$	16,289	$	4	$	(7	)	$	16,286

Long-term
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Agency securities	$	1,000	$	—	$	(1	)	$	999
U.S. Treasury	500		—		—			500
Corporate bonds	752		—		(2		)	750
Certificates of deposit	2,556		—		—			2,556
Total	$	4,808	$	—	$	(3	)	$	4,805

For the years ended December 31, 2015 and 2014, gains or losses realized on the sale of investments were insignificant.

The contractual maturities of the Company's short-term and long-term investments as of December 31, 2015 are as follows (in thousands):



	December 31, 2015
	Amortized Cost		Fair Value
Due in one year or less	$	12,882	$	12,867
Due in one year to five years	3,496		3,490
	$	16,378	$	16,357

When evaluating the investments for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below the amortized cost basis, review of current market liquidity, interest rate risk, the financial condition of the issuer, as well as credit rating downgrades. The Company believes that the unrealized losses are not other-than-temporary. The Company does not have a foreseeable need to liquidate the portfolio and anticipates recovering the full cost of the securities either as market conditions improve, or as the securities mature.

Inventory

The components of inventory consist of the following (in thousands):



	December 31,
	2015		2014
Raw materials	$	9,117	$	7,692
Finished goods	18,978		7,844
Total inventory	$	28,095	$	15,536

Property and equipment, net

Property and equipment, net comprised the following (in thousands):



	December 31,
	2015			2014
Lab equipment, tooling and molds	$	3,228		$	2,766
Computer software	2,019			1,337
Computer equipment ⁽¹⁾	2,757			1,366
Leasehold improvements ⁽¹⁾	1,670			1,070
Furniture and fixtures	950			494
Vehicles	35			35
Total property and equipment	10,659			7,068
Less: Accumulated depreciation and amortization	(5,635		)	(4,111		)
Construction in progress	1,945			767
Property and equipment, net	$	6,969		$	3,724

Depreciation and amortization expense related to property and equipment was $1.7 million, $1.1 million and $1.0 million for the years ended December 31, 2015, 2014 and 2013, respectively.

(1)

During fiscal year 2015, the Company determined that the 2014 leasehold improvements category incorrectly contained computer equipment of $0.4 million. The table above has been revised to correctly reflect these assets within the computer equipment category in the 2014 comparable numbers. The Company concluded that this adjustment was not material to the previously issued consolidated financial statements.

Accrued and Other Current Liabilities

The following table shows the components of accrued liabilities (in thousands):



	December 31,
	2015		2014
Accrued payroll and employee related expenses	$	14,887	$	8,386
Accrued marketing expenses	5,554		2,959
Accrued royalty	5,453		3,612
Sales and other taxes payable	3,703		2,123
Advance payments from customers	1,585		1,908
Accrued legal expenses	1,465		592
Accrued warranty	527		569
Other	1,517		1,301
Total accrued and other current liabilities	$	34,691	$	21,450

Deferred Revenue

The following table shows the components of deferred revenue, including long-term deferred revenue (in thousands):



	December 31,
	2015		2014
Deferred revenue	$	1,347	$	573
Deferred extended warranty revenue	2,902		3,272
Deferred training revenue	3,115		1,381
Other deferred revenue	544		465
Total deferred revenue	$	7,908	$	5,691

Deferred Extended Warranty Revenue

The Company offers standard extended warranties which allows customers to receive service and support which extend beyond the contractual term of the product warranty. The Company recognizes these contracts over the life of the service period. Changes in the Company's deferred revenue, including long-term deferred revenue, related to extended warranties were as follows (in thousands):



	Year Ended December 31,
	2015			2014
Balance at the beginning of the period	$	3,272		$	1,443
Extended warranties issued	3,158			3,897
Amortization	(3,528		)	(2,068		)
Balance at the end of the period	$	2,902		$	3,272

Product Warranties

The estimated product warranty accrual was as follows (in thousands):



	Year Ended December 31,
	2015			2014
Balance at the beginning of the period	$	569		$	676
Settlement of pre-existing warranties	(658		)	(772		)
Provision	616			665
Balance at the end of the period	$	527		$	569