Organization and Summary of Significant Accounting Policies - Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2016 USD ($) customer shares	Mar. 31, 2015 shares	Dec. 31, 2015 USD ($) customer
Concentration Risk [Line Items]
Percentage of cash and cash equivalents held by the Company's main financial institution	62.00%		66.00%
Capitalized stock-based compensation expense included in inventory	$ 2.6		$ 2.5
Total anti-dilutive common stock equivalent shares (in shares) \| shares	11,256,000	6,477,000
Accounts receivable \| Credit concentration risk
Concentration Risk [Line Items]
Concentration risk, percentage			11.00%
Number of customers \| customer	1		1
Prepaid expenses and other current assets \| Bill and Melinda Gates Foundation and National Philanthropic Trust
Concentration Risk [Line Items]
Restricted cash	$ 3.4		$ 2.7

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+ References

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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