Accounting Policies - Additional Information (Detail) - USD ($)
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3 Months Ended |
12 Months Ended |
36 Months Ended |
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Mar. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2016 |
Jan. 31, 2014 |
Feb. 28, 2013 |
| Significant Accounting Policies [Line Items] |
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| Contract revenue |
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$ 16,238,000
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$ 10,298,000
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$ 286,000
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| Liquid investments with a maturity |
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Three months or less
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| Accrued capital expenditures |
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$ 100,000
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$ 100,000
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| Available for sale securities |
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0
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0
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| Payments for Royalties |
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0
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| Gain from insurance proceeds, net |
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682,000
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| Liability for uncertain income tax |
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$ 0
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$ 0
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$ 0
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| Warrants exercise price |
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$ 1.01
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$ 1.01
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$ 1.01
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$ 1.01
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$ 4.50
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$ 1.01
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| Subsequent Event [Member] |
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| Significant Accounting Policies [Line Items] |
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| Additional expense recognized due to adoption of new accounting policy |
$ 200,000
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| Collaboration [Member] |
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| Significant Accounting Policies [Line Items] |
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| Contract revenue |
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$ 600,000
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| Minimum [Member] |
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| Significant Accounting Policies [Line Items] |
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| Estimated useful life of long-lived assets |
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3 years
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| Maximum [Member] |
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| Significant Accounting Policies [Line Items] |
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| Estimated useful life of long-lived assets |
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10 years
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