Balance sheet components
12 Months Ended
Dec. 31, 2015
Balance sheet components  
Balance sheet components

3. Balance sheet components

Cash equivalents and marketable securities

        The following is a summary of cash equivalents and marketable securities (in thousands).

                                                                                                                                                                                    

 

 

December 31, 2015

 

 

 

Amortized
Cost

 

Gross
Unrealized
Gains

 

Gross
Unrealized
Losses

 

Estimated
Fair Value

 

Money market funds

 

$

39,998

 

$

 

$

 

$

39,998

 

U.S. treasury notes

 

 

4,006

 

 

 

 

 

 

4,006

 

U.S. government agency securities

 

 

65,586

 

 

1

 

 

(16

)

 

65,571

 

​  

​  

​  

​  

​  

​  

​  

​  

 

 

$

109,590

 

$

1

 

$

(16

)

$

109,575

 

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

Reported as:

 

 

 

 

 

 

 

 

 

 

 

 

 

Cash equivalents

 

 

 

 

 

 

 

 

 

 

$

50,964

 

Restricted cash

 

 

 

 

 

 

 

 

 

 

 

4,831

 

Marketable securities

 

 

 

 

 

 

 

 

 

 

 

53,780

 

​  

​  

Total cash equivalents, restricted cash and marketable securities

 

 

 

 

 

 

 

 

 

 

$

109,575

 

​  

​  

​  

​  

 

                                                                                                                                                                                    

 

 

December 31, 2014

 

 

 

Amortized
Cost

 

Gross
Unrealized
Gains

 

Gross
Unrealized
Losses

 

Estimated
Fair Value

 

Money market funds

 

$

15,167 

 

$

 

$

 

$

15,167 

 

​  

​  

​  

​  

​  

​  

​  

​  

 

 

$

15,167 

 

$

 

$

 

$

15,167 

 

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

​  

Reported as:

 

 

 

 

 

 

 

 

 

 

 

 

 

Cash equivalents

 

 

 

 

 

 

 

 

 

 

$

15,017 

 

Restricted cash

 

 

 

 

 

 

 

 

 

 

 

150 

 

​  

​  

Total cash equivalents, and restricted cash

 

 

 

 

 

 

 

 

 

 

$

15,167 

 

​  

​  

​  

​  

        The following table summarizes the available-for-sale securities that were in an unrealized loss position as of December 31, 2015, having been in such a position for less than 12 months, and none having been deemed to be other-than-temporarily impaired (in thousands):

                                                                                                                                                                                    

 

 

Gross
Unrealized
Losses

 

Estimated
Fair Value

 

U.S. government agency securities

 

$

16 

 

$

42,034 

 

        None of the available-for-sale securities held as of December 31, 2015 has been in a continuous unrealized loss position for more than one year. As of December 31, 2015, unrealized losses on available-for-sale investments are not attributed to credit risk and are considered to be temporary. The Company believes that it is more-likely-than-not that investments in an unrealized loss position will be held until maturity or the recovery of the cost basis of the investment. To date, the Company has not recorded any impairment charges on marketable securities related to other-than-temporary declines in market value.

        At December 31, 2015, the remaining contractual maturities of available-for-sale securities were less than one year. For the year ended December 31, 2015, realized gains or losses on available-for-sale securities were de minimis. There were no available-for-sale marketable securities held by the Company at December 31, 2014.

Property and equipment, net

        Property and equipment consisted of the following (in thousands):

                                                                                                                                                                                    

 

 

December 31,

 

 

 

2015

 

2014

 

Leasehold improvements

 

$

2,548

 

$

1,914

 

Laboratory equipment

 

 

10,461

 

 

6,528

 

Equipment under capital lease

 

 

8,224

 

 

3,735

 

Computer equipment

 

 

2,397

 

 

1,156

 

Software

 

 

2,368

 

 

831

 

Furniture and fixtures

 

 

210

 

 

158

 

Automobiles

 

 

20

 

 

 

Construction-in-progress

 

 

1,202

 

 

4,853

 

​  

​  

​  

​  

Total property and equipment, gross

 

 

27,430

 

 

19,175

 

Accumulated depreciation and amortization

 

 

(8,721

)

 

(3,503

)

​  

​  

​  

​  

Total property and equipment, net

 

$

18,709

 

$

15,672

 

​  

​  

​  

​  

​  

​  

​  

​  

        Included in the construction-in-progress balance as of December 31, 2014 was $2.9 million of capital lease equipment that had not been placed in service. Depreciation and amortization expense was $5.3 million, $2.3 million and $0.9 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Accrued liabilities

        Accrued liabilities consisted of the following (in thousands):

                                                                                                                                                                                    

 

 

Year ended
December 31,

 

 

 

2015

 

2014

 

Accrued compensation and related expenses

 

$

2,307 

 

$

1,439 

 

Accrued laboratory materials purchases

 

 

426 

 

 

 

Accrued professional services

 

 

272 

 

 

1,030 

 

Accrued costs for construction-in-progress

 

 

 

 

32 

 

Other

 

 

1,248 

 

 

736 

 

​  

​  

​  

​  

Total accrued liabilities

 

$

4,253 

 

$

3,237 

 

​  

​  

​  

​  

​  

​  

​  

​